Quantum dot electroluminescence device

ABSTRACT

A device having design film thicknesses, to suppress non-uniformity of a light emitting surface, to provide a quantum dot electroluminescence device with good luminous efficiency and light emitting life-span, and to provide an excellent quantum dot electroluminescence device with luminous efficiency and light emitting life-span. A quantum dot electroluminescence device including a hole transport layer, an electron transport layer, and a light emitting layer disposed between the hole transport layer and the electron transport layer, wherein the hole transport layer includes a polymer material and a low molecular material, the light emitting layer includes a quantum dot having a core-shell structure, and a residual film ratio of the hole transport layer is greater than or equal to about 95%.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Japanese Patent Application No.2018-248419 filed on Dec. 28, 2018, in the Japan Patent Office, andKorean Patent Application No. 10-2019-0176495 filed in the KoreanIntellectual Property Office on Dec. 27, 2019, and all the benefitsaccruing therefrom under 35 U.S.C. § 119, the entire content of which isherein incorporated by reference.

BACKGROUND 1. Field

The present disclosure relates to a quantum dot electroluminescencedevice.

2. Description of the Related Art

Recently, organic electroluminescence devices (hereinafter, alsoreferred to as organic light emitting diodes) using organic materialshave attracted attention. Organic light emitting diodes are thin,lightweight, and have low power consumption, and thus are used asdisplay devices, televisions, and lighting devices of portable phones.

However, the organic light emitting diodes have a wide full width athalf maximum (FWHM) of the light emitting spectrum, which makes itdifficult to cope with the narrowing of the light emitting spectrum,which is required for higher precision and color gamut expansion. As amethod of solving this problem, a technique using “a quantum dot”, whichis an inorganic light emitting material, has attracted attention. Aquantum dot electroluminescence device (hereinafter, also referred to asa “quantum dot EL device”, a “QLED”, etc.) having a light emitting layerincluding a quantum dot has improved durability since the light emittingmaterial is an inorganic compound, and a relatively long life-span of adevice emission may be expected. In addition, since the quantum dot hasa feature capable of being dispersed in various solvents, the quantumdot EL device may be manufactured by a wet coating method with anassociated low cost and high productivity.

is not sufficient to increase high performance of charge transportingmaterials disposed near thereto, to optimize a device structure, and toincrease high performance of the quantum dot itself. The technicalchallenge to develop a high performance quantum dot EL device, such as adevice with long light emitting life-span, high efficiency, colorpurity, low driving voltage, and the like remains. Moreover, thedevelopment of new charge transporting materials to develop a highperformance device structure is likely in itself to be insufficient, andtherefore, an effort to develop high performing quantum dots isnecessary.

Patent Reference 1 (International publication No. WO2015/105027)discloses a light emitting device having the following structure: amonga hole transport layer and the electron transport layer, a carriertransporting material having the same transportability as a transportlayer having a small carrier mobility is provided between quantum dotsin a form of a dispersion type. More specifically, in examples of thispatent publication, poly-TPD(N,N′-diphenyl-N,N′-bis(3-methylphenyl)-[1,1′-biphenyl]-4,4′-diamine) isused as a polymer-based hole transporting material in the hole transportlayer. In addition, CBP (4,4′-bis(2,2-carbazole-9-yl) biphenyl) is usedas a soluble hole transporting material to facilitate the dispersion ofquantum dots in the transport material. In this light emitting device,the CBP is present in the quantum dot layer as a dispersion type,thereby improving hole injection efficiency for the quantum dots,thereby improving the carrier balance. As a result, a decrease inprobability of recombination in the hole transport layer reduces thelight emission from poly-TPD, and increasing probability ofrecombination in the quantum dot layer. As a result, since luminousefficiency is improved, luminous efficiency or light emitting colorpurity is good, and a light emitting device capable of lowering drivingvoltage is obtained.

SUMMARY

The technical solution described in Patent Reference 1 is that a holetransport layer is dissolved in a solvent and this facilitates forming alight emitting layer with transport material dispersed between quantumdots. However, there is a concern that a non-uniformity or roughness ofthe light emitting surface may occur, or leakage current may increasefrom thin portions of a resulting film. In general, a device having anon-uniform light emitting layer, or a device with increasing leakagecurrent at a light emitting surface may have insufficient life-span.

Accordingly, the present disclosure is to provide a quantum dotelectroluminescence device capable of constructing devices having adesign film thickness, suppressing non-uniform light emitting surfaces,and having good luminous efficiency and light emitting life-span. Ourinvestigations in addressing these areas and technical challenges hasprovided a QLED having a hole transport layer including a polymermaterial and a low molecular material and having a residual film ratioof about 95% or more. That is, according to an embodiment, a quantum dotelectroluminescence device includes a hole transport layer, an electrontransport layer, and a light emitting layer disposed between the holetransport layer and the electron transport layer, wherein the holetransport layer includes a polymer material and a low molecularmaterial, the light emitting layer includes a quantum dot having acore-shell structure, and a residual film ratio of the hole transportlayer is greater than or equal to about 95%.

According to the present disclosure, a device having a design filmthickness may be constructed, a non-uniformity of a light emittingsurface may be suppressed, and a quantum dot electroluminescence devicehaving both good luminous efficiency and light emitting life-span may beprovided.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view showing a quantum dot electroluminescencedevice according to an embodiment.

DETAILED DESCRIPTION

The present disclosure provides a quantum dot electroluminescence deviceincluding a hole transport layer, an electron transport layer, a lightemitting layer disposed between the hole transport layer and theelectron transport layer, wherein the hole transport layer includes apolymer material and a low molecular material, the light emitting layerincludes a quantum dot having a core-shell structure, and a residualfilm ratio of the hole transport layer is greater than or equal to about95%.

The quantum dot electroluminescence device of the present disclosurehaving such a configuration may construct devices according to thedesign film thickness, suppress non-uniformity of the light emittingsurface, and have improved luminous efficiency and light emittinglife-span.

In patent reference 1, in order to disperse the carrier transportingmaterial between quantum dots, it is first necessary to dissolve thecarrier transport layer with a solvent. As a result, the surface of thecarrier transport layer can become relatively non-uniform or exhibit anincrease in roughness, and leakage current maybe generated from thinportions of the film. In addition, these two affects may individuallycontribute to a decrease in the light emitting life-span of the device.

Our work in this area sought to address the above technical challengesand describe herein a quantum dot EL device that includes a holetransport including a polymer material and a low molecular material, anda light emitting layer including a quantum dot having a core-shellstructure, and a residual film ratio of the hole transport layer isgreater than or equal to about 95%.

The hole transport layer according to the present disclosure includes apolymer material and a low molecular material. Because the low molecularmaterial may enter gaps of the polymer transport material, it becomes amore dense hole transport layer, which is believed to improve holetransport capability of the hole transport layer.

In addition, the light emitting layer according to the presentdisclosure, when formed on the hole transport layer, can provide adesign film thickness with good reproducibility. In addition, becausesurface smoothness of the hole transport layer may be improved, i.e.,reduced, it is possible to suppress the non-uniformity of the lightemitting surface, and suppress the occurrence of leakage current.Therefore, the quantum dot electroluminescence device of the presentdisclosure has improved luminous efficiency and light emittinglife-span. The above stated mechanism is based on our work and beliefs,and whether correct or not, such statements are not to diminish thescope of the present disclosure, nor the technical scope of the subjectmatter claimed.

Hereinafter, embodiments of the present disclosure are described. Thepresent disclosure is not limited only to the following embodiments. Inaddition, each drawing is exaggerated for better understanding and easeof description, and a dimensional ratio of each constituent element ineach drawing may be different from the actual one.

It will be understood that when an element is referred to as being “on”another element, it can be directly on the other element or interveningelements may be present therebetween. In contrast, when an element isreferred to as being “directly on” another element, there are nointervening elements present.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting. As used herein, thesingular forms “a,” “an,” and “the” are intended to include the pluralforms, including “at least one,” unless the content clearly indicatesotherwise. “At least one” is not to be construed as limiting “a” or“an.” “Or” means “and/or.” As used herein, the term “and/or” includesany and all combinations of one or more of the associated listed items.It will be further understood that the terms “comprises” and/or“comprising,” or “includes” and/or “including” when used in thisspecification, specify the presence of stated features, regions,integers, steps, operations, elements, and/or components, but do notpreclude the presence or addition of one or more other features,regions, integers, steps, operations, elements, components, and/orgroups thereof.

“About” or “approximately” as used herein is inclusive of the statedvalue and means within an acceptable range of deviation for theparticular value as determined by one of ordinary skill in the art,considering the measurement in question and the error associated withmeasurement of the particular quantity (i.e., the limitations of themeasurement system). For example, “about” can mean within one or morestandard deviations, or within ±30%, 20%, 10% or 5% of the stated value.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this disclosure belongs. It willbe further understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art and thepresent disclosure, and will not be interpreted in an idealized oroverly formal sense unless expressly so defined herein. As used herein,unless specifically stated, operations such as film formation areactually performed in a glove box, and are carried out under conditionsof room temperature (greater than or equal to about 20° C. and less thanor equal to about 25° C.) and oxygen concentration of less than or equalto about 1 ppm/moisture concentration of less than or equal to about 1ppm. Properties, and the like are measured under the conditions of roomtemperature (greater than or equal to about 20° C. and less than orequal to about 25° C.) and relative wet humidity of greater than orequal to about 40% RH and less than or equal to about 50% RH.

Hereinafter, the polymer material and the low molecular materialincluded in the hole transport layer and the hole transport layer aredescribed. In this specification, the hydrogen atom included in thepolymer material and the low molecular material may be a deuterium atom.

Hole Transport Layer

The polymer material that constitutes the hole transport layer of thepresent disclosure may desirably have a HOMO energy level of greaterthan or equal to about 5.3 electron volts (eV) and less than or equal toabout 6.2 eV. Within the range, holes may be efficiently transported tothe light emitting layer, the driving voltage of the device may bereduced, and the luminous efficiency may be improved. The HOMO energylevel of the polymer material is desirably greater than or equal toabout 5.4 eV and less than or equal to about 5.7 eV.

In this specification, the HOMO energy levels of the polymer materialand the low molecular material are values of ionization potentialsmeasured using the photoelectron spectrometer AC-3 (made by HitachiHigh-Technologies Corporation) in an air atmosphere.

Polymer Material

The polymer material, which constitutes the hole transport layer of thepresent disclosure, may desirably have a weight average molecular weight(Mw) of about 10,000 grams per mole (g/mole) to about 1,000,000 g/mole.Within the range, since a residual ratio of a film may be improved andlamination properties may be improved, it is possible to form a stableuniform hole transport layer. In addition, a viscosity of the solutionmay be lowered, inkjet suitability may be improved, and it is possibleto form a uniform hole transport layer stably by a coating method. Thepolymer material may desirably have a weight average molecular weight(Mw) of greater than or equal to about 30,000 g/mole and less than orequal to about 600,000 g/mole, and more desirably greater than or equalto about 80,000 g/mole and less than or equal to about 450,000 g/mole.

The measurement of the weight average molecular weight (Mw) of thepolymer material is not particularly limited and may be applied by usinga known method or by appropriately changing the known methods. In thepresent specification, the weight average molecular weight (Mw) uses avalue measured by the following method.

Measurement of Weight Average Molecular Weight (Mw)

The weight average molecular weight (Mw) of the polymer material ismeasured under the following conditions by SEC (Size ExclusionChromatography) using polystyrene as a standard material.

(SEC Measurement Condition)

Analysis equipment (SEC): Shimadzu Corporation, Prominence

Column: Polymer Laboratories, PLgel MIXED-B

Column temperature: 40° C.

Flow rate: 1.0 mL/min

Injection amount of sample solution: 20 microliter (μL) (concentration:about 0.05 weight percent)

Eluent: tetrahydrofuran (THF)

Detector (UV-VIS detector): Shimadzu Corporation, SPD-10AV

Standard sample: polystyrene.

The number average molecular weight (Mn) and polydispersity (Mw/Mn) ofthe polymer material may also be measured by the same method asdescribed above.

When the polymer material is a copolymer composed of two or morestructural units, the structure of the polymer material is notparticularly limited. The polymer material may be any of randomcopolymer, alternate copolymer, periodic copolymer, and block copolymer.

The polymer compound of the present embodiment desirably has an aminestructure. By including the amine structure, the hole transport propertymay be improved.

The polymer material of the present embodiment may be synthesized byusing a known organic synthesis method. The specific synthesis method ofthe polymer material of the present embodiment may be easily understoodby a person of an ordinary skill in the art referring to the followingexamples. The monomers used for the polymerization of the polymermaterial may be synthesized by appropriately combining known synthesisreactions and their structures may be confirmed by known methods (forexample, NMR, LC-MS, etc.).

Hereinafter, polymer compounds 1 to 6, which are desirable embodimentsof the polymer material, are described. The polymer materials may beused individually or in combination of two or more types.

Polymer Compound 1

According to the preferred embodiment of the present disclosure, thepolymer material includes a polymer compound (hereinafter simplyreferred to also as “polymer compound 1”) including a segment of analternate copolymer of a structural unit represented by ChemicalFormula 1. According to a more desirable embodiment, the polymermaterial is polymer compound 1.

The polymer compound 1 includes a segment of an alternate copolymer ofthe structural unit represented by Chemical Formula 1.

In Chemical Formula 1, X is a group represented by Chemical Formula 2, Yis a substituted or unsubstituted C6 to 60 divalent aromatic hydrocarbongroup, or a substituted or unsubstituted divalent aromatic heterocyclicgroup having 3 to 60 ring-forming atoms.

In Chemical Formula 2, Ar₁ is a substituted or unsubstituted C6 to C60trivalent aromatic hydrocarbon group, or a substituted or unsubstitutedtrivalent aromatic heterocyclic group having 3 to 60 ring-forming atoms,

Ar₂ and Ar₃ are independently a substituted or unsubstituted C6 to C60monovalent aromatic hydrocarbon group, or a substituted or unsubstitutedmonovalent aromatic heterocyclic group having 3 to 60 ring-formingatoms,

L₁ and L₂ are independently a single bond, a substituted orunsubstituted C6 to C60 divalent aromatic hydrocarbon group, or asubstituted or unsubstituted divalent aromatic heterocyclic group having3 to 60 ring-forming atoms,

R₁ and R₂ are independently, a substituted or unsubstituted C1 to C20alkyl group, a substituted or unsubstituted C1 to C20 alkoxy group, asubstituted or unsubstituted C6 to C60 monovalent aromatic hydrocarbongroup, or a substituted or unsubstituted monovalent aromaticheterocyclic group having 3 to 60 ring-forming atoms, or

R₁ and R₂ are linked to each other to form a ring,

a is an integer of 0 to 4,

b is an integer of 0 to 3, and

Z₁ to Z4 are independently a nitrogen atom, CH or CR₁; and

Z₅ to Z₈ are independently a nitrogen atom, CH, or CR₂, and where one ofZ₅ to Z₈ is connected to L₂.

The polymer compound 1 may include one or more structural unitsrepresented by Chemical Formula 1, and may further include one or moreother structural units. Herein, the polymer compound 1 includes asegment of the alternate copolymer in which X and Y are alternatelybonded, and thus the reproducibility of the preparation is high. Inaddition, since the polymer compound 1 has no localization of X and Y,homogeneous characteristics may be obtained when used as a thin film.

The polymer compound 1 may include one type of X or two or more types ofX as a structural unit.

The polymer compound 1 may improve hole transport properties because Xincludes a nitrogen-containing aromatic heterocycle (for example,carbazole backbone) substituted with an amino group.

In addition, in the polymer compound 1, X includes an aromatic group(Ar₁) in the main chain and an amino group (N(Ar₂)(Ar₃)) that binds anitrogen-containing aromatic heterocycle and a nitrogen-containingaromatic heterocycle in the side chain. For this reason, the polymercompound 1 has a deep HOMO level, and as a result, may achieve highluminous efficiency and a low driving voltage in the quantum dot lightemitting device.

In Chemical Formula 2, Ar₁ may be a substituted or unsubstituted C6 toC60 trivalent aromatic hydrocarbon group or a substituted orunsubstituted trivalent aromatic heterocyclic group having 3 to 60ring-forming atoms.

Herein, the aromatic hydrocarbon group is a group derived from anaromatic hydrocarbon compound including at least one aromatichydrocarbon ring. Herein, when the aromatic hydrocarbon group includestwo or more aromatic hydrocarbon rings, the two or more aromatichydrocarbon rings may be compensated with each other. In addition, thearomatic hydrocarbon group may be substituted with one or moresubstituents.

Examples of aromatic hydrocarbon compounds may include, for examplebenzene, pentalene, indene, naphthalene, anthracene, azulene, heptalene,acenaphthalene, phenalene, fluorene, anthraquinone, phenanthrene,biphenyl, triphenylene, pyrene, chrysene, pycene, perylene, pentaphene,pentacene, tetraphene, hexaphene, hexacene, rubicene, trinaphthylene,heptaphene, and pyrantrene, but are not particularly limited thereto.

In addition, the aromatic heterocyclic group is a group derived from anaromatic heterocycle compound including at least one aromaticheterocycle having at least one heteroatom (for example, nitrogen atom(N), oxygen atom (O), phosphorus atom (P), and sulfur atom (S)), and theremaining ring-forming carbon atom (C). In addition, when the aromaticheterocyclic group includes two or more aromatic heterocycles, two ormore aromatic heterocycles may be condensed with each other. Thearomatic heterocyclic group may be substituted with one or moresubstituents.

The aromatic heterocycle compounds may include, for example, pyrazoline,imidazoline, oxazoline, thiazoline, triazoline, tetrazoleline,oxadiazoline, pyridine, pyridazinine, pyrimidine, triazine, carbazoline,azacarbazoline, indoline, quinolinine, isoquinoline, benzimidazoline,imidazopyridine, imidazopyrimidine, furan, benzofuran, dibenzofuran,azadibenzofuran, thiophene, benzothiophene, dibenzothiophene,azadibenzothiophene, and the like, but are not particularly limitedthereto.

Examples of the trivalent aromatic hydrocarbon groups in Ar₁ may be agroup obtained by removing any three hydrogen atoms from the hydrogenatoms of the aromatic hydrocarbon compound. In addition, examples of thetrivalent aromatic heterocyclic group may be a group obtained byremoving any three hydrogen atoms from the hydrogen atoms of thearomatic heterocycle compound.

Among them, from the viewpoint of adjusting the HOMO level, it isdesirably that Ar₁ may be the following groups.

In the chemical formulae, A is —O—, —S—, —Se—, —NR₁— (R₁ is hydrogen,deuterium atom, a substituted or unsubstituted alkyl group, asubstituted or unsubstituted aryl group or a substituted orunsubstituted heteroaryl group) or —CR₂R₃— (R₂ and R₃ are independentlya hydrogen atom, a deuterium atom, a substituted or unsubstituted alkylgroup, a substituted or unsubstituted aryl group, or a substituted orunsubstituted heteroaryl group), and * is a linking portion.

Substituents when the trivalent aromatic hydrocarbon group or thetrivalent aromatic heterocyclic group is substituted may include, forexample, a halogen atom, an alkyl group, an alkoxy group, an aromatichydrocarbon group, and an aromatic heterocyclic group, but are notparticularly limited thereto. The above substituents may also be usedtogether.

Herein, examples of the halogen atom may include for example, a fluorineatom, a chlorine atom, a bromine atom, and an iodine atom.

The alkyl group may include, for example, a methyl group, an ethylgroup, an n-propyl group, a isopropyl group, an n-butyl group, anisobutyl group, a sec-butyl group, a tert-butyl group, an n-pentylgroup, an isopentyl group, a tert-pentyl group, a neopentyl group, a1,2-dimethylpropyl group, an n-hexyl group, a isohexyl group, a1,3-dimethylbutyl group, a 1-isopropylpropyl group, a 1,2-dimethylbutylgroup, an n-heptyl group, a 1,4-dimethylpentyl group, 3-ethylpentylgroup, a 2-methyl-1-isopropylpropyl group, a 1-ethyl-3-methylbutylgroup, an n-octyl group, a 2-ethylhexyl group, a3-methyl-1-isopropylbutyl group, a 2-methyl-1-isopropylbutyl group, a1-tert-butyl-2-methylpropyl group, an n-nonyl group, a3,5,5-trimethylhexyl group, an n-decyl group, a isodecyl group, ann-undecyl group, a 1-methyldecyl group, an n-dodecyl group, ann-tridecyl group, an n-tetradecyl group, an n-pentadecyl group, ann-hexadecyl group, an n-heptadecyl group, an n-octadecyl group, ann-nonadecyl group, an n-eicosyl group, an n-heneicosyl group, ann-docosyl group, an n-tricosyl group, and an n-tetracosyl group.

The carbon number of the alkyl group is more desirably in the followingtype.

For example, when the ligand of the quantum dot is a long chainalkyl-containing compound such as oleic acid, oleylamine, ortrioctylphosphine, the compound included in the hole transport layer mayalso desirably include a compound having a long chain alkyl group. Thisis because the ligand of the quantum dot and the alkyl group present inthe hole transport layer may interact with each other, thereby improvingeffects such as hole injectability.

In addition, when the solvent that disperses the quantum dot is along-chain hydrocarbon-based solvent, it is desirable that the number ofthe alkyl group in the polymer compound is small in terms of securing aresidual film ratio of the hole transport layer.

Therefore, as the substituent, hydrogen, or a linear or branched C1 toC18 alkyl group is more desirable. These substituents may beappropriately selected according to the used quantum dot or the solventthat disperses the quantum dot.

The alkoxy group may include, for example, a methoxy group, an ethoxygroup, a propoxy group, an isopropoxy group, a butoxy group, a pentyloxygroup, a hexyloxy group, a heptyloxy group, an octyloxy group, anonyloxy group, a decyloxy group, a undecyloxy group, a dodecyloxygroup, a tridecyloxy group, a tetradecyloxy group, a pentadecyloxygroup, a hexadecyloxy group, a heptadecyloxy group, an octadecyloxygroup, a 2-ethylhexyloxy group, or a 3-ethylpentyloxy group.

The carbon number of the alkoxy group is more desirably in the followingtype.

For example, when the ligand of the quantum dot is a long chainalkyl-containing compound such as oleic acid, oleylamine, ortrioctylphosphine, the compound included in the hole transport layer mayalso desirably include a compound having a long chain alkoxy group. Thisis because the ligand of the quantum dot and the alkoxy group present inthe hole transport layer may interact with each other, thereby improvingeffects such as hole injectability.

In addition, when the solvent that disperses the quantum dot is along-chain hydrocarbon-based solvent, it is desirable that the number ofthe alkoxy group in the polymer compound is small in terms of securing aresidual film ratio of the hole transport layer.

Therefore, as the alkoxy group, a linear or branched C1 to C18 alkoxygroup is more desirable. These alkoxy groups may be appropriatelyselected according to the used quantum dot or the solvent that dispersesthe quantum dot.

Examples of the aromatic heterocyclic group (or aromatic hydrocarbongroup) which may be introduced into the trivalent aromatic hydrocarbongroup (or trivalent aromatic heterocyclic group) may include, forexample, a group obtained by removing any one hydrogen atom from thearomatic heterocycle (or aromatic hydrocarbon).

In Chemical Formula 2, Ar₂ and Ar₃ are independently a substituted orunsubstituted C6 to C60 monovalent aromatic hydrocarbon group, or asubstituted or unsubstituted monovalent aromatic heterocyclic grouphaving 3 to 60 ring-forming atoms.

Herein, the monovalent aromatic hydrocarbon group and the monovalentaromatic heterocyclic group are the same as Ar₁ in Chemical Formula 2,except that the trivalent aromatic heterocyclic group and the trivalentaromatic heterocyclic group are changed into monovalent groups, and thusthe descriptions thereof are omitted. In addition, when the monovalentaromatic hydrocarbon group or the monovalent aromatic heterocyclic groupis substituted, the substituent is the same as the substituent of Ar₁ inChemical Formula 2, and thus the descriptions thereof are omitted.

From the viewpoint of raising the HOMO level, hole transport property,and hole injection property of the polymer compound 1, the monovalentaromatic hydrocarbon group may desirably be a phenyl group, a biphenylgroup, a fluorenyl group, a naphthyl group, an anthryl group, aphenanthryl group, a naphthacenyl group, a pyrenyl group, a terphenylgroup, a tolyl group, a tert-butylphenyl group, or a(phenylpropyl)phenyl group, and more desirably a phenyl group, abiphenyl group, a fluorenyl group, a naphthyl group, an anthryl group, aterphenyl group, or a tolyl group.

In addition, from the viewpoint of raising the HOMO level, holetransport property, and hole injection property of the polymer compound1, the monovalent aromatic heterocyclic group may desirably be a pyridylgroup, a bipyridyl group, a pyrrolyl group, a pyrazinyl group, apyridinyl group, a pyridmidyl group, an indolyl group, a puryl group, abenzofuranyl group, a dibenzofuranyl group, a quinolyl group, aquinoxanyl group, a carbazolyl group, a phenantridinyl group, anacridinyl group, a phenazinyl group, a phenothiazinyl group, aphenoxazinyl group, an oxazolyl group, an oxathiazolyl group, afurazanyl group, a thienyl group, a thiophenyl group, an isothiophenylgroup, or a dibenzothiophenyl group, and more desirably a pyridyl group,a pyrrolyl group, a carbazolyl group, a dibenzofuranyl group, adibenzothiophenyl group, or a bipyridyl group.

In addition, from the viewpoint of raising the HOMO level, holetransport property, hole injection property, solubility, and coatingproperty of the polymer compound 1, when the monovalent aromatichydrocarbon group or the monovalent aromatic heterocyclic group issubstituted, the substituent may desirably be a C1 to C 18 alkyl group,a C1 to C18 alkoxy group, an alkylthio group, an aryl group, an aryloxygroup, an arylthio group, an arylalkyl group, an arylalkoxy group, anarylalkylthio group, an arylalkenyl group, an arylalkynyl group, anamino group, an amino group substituted with the substituent, a silylgroup, a substituted silyl group, a halogen atom, an acyl group, anacyloxy group, an imine moiety, an amide group, an acidimide group, amonovalent heterocyclic group, a carboxyl group, a carboxyl groupsubstituted with the substituent, a cyano group, or a nitro group.

Examples of Ar₂ and Ar₃ may be as follows.

In the chemical formulae, R₃ is independently a substituted orunsubstituted C1 to C20 alkyl group, a substituted or unsubstituted C1to C20 alkoxy group, a substituted or unsubstituted C6 to C60 monovalentaromatic hydrocarbon group, or a substituted or unsubstituted monovalentaromatic heterocyclic group having 3 to 60 ring-forming atoms, * is alinking portion, and “Alkyl” indicates substitution or unsubstitutionwith an alkyl group.

The carbon number of the alkyl group is more desirably in the followingtype.

For example, when the ligand of the quantum dot is a long chainalkyl-containing compound such as oleic acid, oleylamine, ortrioctylphosphine, the compound included in the hole transport layer mayalso desirably include a compound having a long chain alkyl group. Thisis because the ligand of the quantum dot and the alkyl group present inthe hole transport layer may interact with each other, thereby improvingeffects such as hole injectability.

In addition, when the solvent that disperses the quantum dot is along-chain hydrocarbon-based solvent, it is desirable that the number ofthe alkyl group in the polymer compound is small in terms of securing aresidual film ratio of the hole transport layer.

Therefore, as the alkyl group, a linear or branched C1 to C18 alkylgroup is more desirable. The alkyl group may be appropriately selectedaccording to the used quantum dot or the solvent that disperses thequantum dot.

The carbon number of the alkoxy group is more desirably in the followingtype.

For example, when the ligand of the quantum dot is a long chainalkyl-containing compound such as oleic acid, oleylamine, ortrioctylphosphine, the compound included in the hole transport layer mayalso desirably include a compound having a long chain alkoxy group. Thisis because the ligand of the quantum dot and the alkoxy group present inthe hole transport layer may interact with each other, thereby improvingeffects such as hole injectability.

In addition, when the solvent that disperses the quantum dot is along-chain hydrocarbon-based solvent, it is desirable that the number ofthe alkoxy group in the polymer compound is small in terms of securing aresidual film ratio of the hole transport layer.

Therefore, as the alkoxy group, a linear or branched C1 to C18 alkoxygroup is more desirable. These alkoxy groups may be appropriatelyselected according to the used quantum dot or the solvent that dispersesthe quantum dot.

In Chemical Formula 2, L₁ and L₂ are independently a single bond, asubstituted or unsubstituted C6 to C60 divalent aromatic hydrocarbongroup, or a substituted or unsubstituted divalent aromatic heterocyclicgroup having 3 to 60 ring-forming atoms.

Herein, the divalent aromatic hydrocarbon group and the divalentaromatic heterocyclic group are the same as Ar₁ in Chemical Formula 2,except that the trivalent aromatic heterocyclic group and the trivalentaromatic heterocyclic group are changed divalent groups, and thus thedescriptions thereof are omitted. In addition, when the divalentaromatic hydrocarbon group or the divalent aromatic heterocyclic groupis substituted, the substituent is the same as the substituent of Ar₁ inChemical Formula 2, and thus the descriptions thereof are omitted.

From the viewpoint of raising the HOMO level, hole transport property,and hole injection property of the polymer compound 1, the divalentaromatic hydrocarbon group may desirably be a phenylene group, abiphenylene group, a fluorenylene group, a naphthylene group, ananthrylene group, a phenanthrylene group, a naphthacenylene group, apyrenylene group, a terphenylene group, a tolylene group, atert-butylphenylene group, or a (phenylpropyl)phenylene group, and moredesirably a phenylene group, a biphenylene group, a fluorenylene group,a naphthylene group, an anthrylene group, a terphenylene group, or atolylene group.

In addition, from the viewpoint of raising the HOMO level, holetransport property, and hole injection property of the polymer compound1, the divalent aromatic heterocyclic group may desirably be a pyridylgroup, a bipyridyl group, a pyrrolyl group, a pyrazinyl group, apyridinyl group, a pyridmidyl group, an indolyl group, a puryl group, abenzofuranyl group, a dibenzofuranyl group, a quinolyl group, aquinoxanyl group, a carbazolyl group, a phenantridinyl group, anacridinyl group, a phenazinyl group, a phenothiazinyl, a phenoxazinylgroup, an oxazolyl group, an oxathiazolyl group, a furazanyl group, athienyl group, a thiophenyl group, an isothiophenyl group, or adibenzothiophenyl group, and more desirably a pyridyl group, a pyrrolylgroup, a carbazolyl group, a dibenzofuranyl group, a dibenzothiophenylgroup, or bipyridyl group.

In addition, from the viewpoint of raising the HOMO level, holetransport property, hole injection property, solubility, and coatingproperty of the polymer compound 1, when the divalent aromatichydrocarbon group or the divalent aromatic heterocyclic group issubstituted, the substituent may desirably be a C1 to C50 alkyl group,an alkoxy group, an alkylthio group, an aryl group, an aryloxy group, anarylthio group, an arylalkyl group, an arylalkoxy group, anarylalkylthio group, an arylalkenyl group, an arylalkynyl group, anamino group, an amino group substituted with the substituent, an silylgroup, an substituted silyl group, an a halogen atom, an acyl group, anacyloxy group, an imine moiety, an amide group, an acidimide group, anmonovalent heterocyclic group, a carboxyl group, a carboxyl groupsubstituted with the substituent, an a cyano group, or an nitro group,and more desirably a C1 to C50 alkyl group.

The carbon number of the alkyl group is more desirably in the followingtype.

For example, when the ligand of the quantum dot is a long chainalkyl-containing compound such as oleic acid, oleylamine, ortrioctylphosphine, the compound included in the hole transport layer mayalso desirably include a compound having a long chain alkyl group. Thisis because the ligand of the quantum dot and the alkyl group present inthe hole transport layer may interact with each other, thereby improvingeffects such as hole injectability.

In addition, when the solvent that disperses the quantum dot is along-chain hydrocarbon-based solvent, it is desirable that the number ofthe alkyl group in the polymer compound is small in terms of securing aresidual film ratio of the hole transport layer.

Therefore, as the alkyl group, a linear or branched C1 to C18 alkylgroup is more desirable. The alkyl group may be appropriately selectedaccording to the used quantum dot or the solvent that disperses thequantum dot.

The carbon number of the alkoxy group is more desirably in the followingtype.

For example, when the ligand of the quantum dot is a long chainalkyl-containing compound such as oleic acid, oleylamine, ortrioctylphosphine, the compound included in the hole transport layer mayalso desirably include a compound having a long chain alkoxy group. Thisis because the ligand of the quantum dot and the alkoxy group present inthe hole transport layer may interact with each other, thereby improvingeffects such as hole injectability.

In addition, when the solvent that disperses the quantum dot is along-chain hydrocarbon-based solvent, it is desirable that the number ofthe alkoxy group in the polymer compound is small in terms of securing aresidual film ratio of the hole transport layer.

Therefore, as the alkoxy group, a linear or branched C1 to C18 alkoxygroup is more desirable. These alkoxy groups may be appropriatelyselected according to the used quantum dot or the solvent that dispersesthe quantum dot.

Among these, L₁ and L₂ are independently desirably a single bond, aphenylene group, a biphenylene group, a fluorenylene group, anaphthylene group, an anthracenylene group, a phenanthrylene group, anaphthacenylene group, a pyrenylene group, a terphenylene group, atolylene group, a tert-butylphenylene group, or a (phenylpropyl)phenylene group, and more desirably a single bond, a phenylene group, abiphenylene group, a terphenylene group, or a fluorenylene group.

In Chemical Formula 2, R₁ and R₂ are independently a substituted orunsubstituted C1 to C20 alkyl group, a substituted or unsubstituted C1to C20 alkoxy group, a substituted or unsubstituted C6 to C60 monovalentaromatic hydrocarbon group, or a substituted or unsubstituted monovalentaromatic heterocyclic group having 3 to 60 ring-forming atoms.Optionally, two adjacent R₁ and/or two adjacent R₂ may be linked to eachother to form a ring. R₁ and R₂ may be the same or different. Inaddition, when a is greater than or equal to 2 and less than or equal to4, each R₁ may be the same and may be different. In the same way, when bis 2 or 3, each R₂ may be the same and may be different.

Herein, the C1 to C20 alkyl group may include a methyl group, an ethylgroup, an n-propyl group, an isopropyl group, an n-butyl group, anisobutyl group, a sec-butyl group, a tert-butyl group, an n-pentylgroup, an isopentyl group, a tert-pentyl group, a neopentyl group, a1,2-dimethylpropyl group, an n-hexyl group, an isohexyl group, a1,3-dimethylbutyl group, a 1-isopropylpropyl group, a 1,2-dimethylbutylgroup, an n-heptyl group, a 1,4-dimethylpentyl group, a 3-ethylpentylgroup, a 2-methyl-1-isopropylpropyl group, a 1-ethyl-3-methylbutylgroup, an n-octyl group, a 2-ethylhexyl group, a3-methyl-1-isopropylbutyl group, a 2-methyl-1-isopropylbutyl group, a1-tert-butyl-2-methylpropyl group, an n-nonyl group, a3,5,5-trimethylhexyl group, an n-decyl group, an isodecyl group, ann-undecyl group, a 1-methyldecyl group, an n-dodecyl group, ann-tridecyl group, an n-tetradecyl group, an n-pentadecyl group, ann-hexadecyl group, an n-heptadecyl group, an n-octadecyl group, ann-eicosyl group, and the like, but is not particularly limited thereto.

The carbon number of the alkyl group is more desirably in the followingtype.

For example, when the ligand of the quantum dot is a long chainalkyl-containing compound such as oleic acid, oleylamine, ortrioctylphosphine, the compound included in the hole transport layer mayalso desirably include a compound having a long chain alkyl group. Thisis because the ligand of the quantum dot and the alkyl group present inthe hole transport layer may interact with each other, thereby improvingeffects such as hole injectability.

In addition, when the solvent that disperses the quantum dot is along-chain hydrocarbon-based solvent, it is desirable that the number ofthe alkyl group in the polymer compound is small in terms of securing aresidual film ratio of the hole transport layer.

Therefore, as the alkyl group, a linear or branched C1 to C18 alkylgroup is more desirable. The alkyl group may be appropriately selectedaccording to the used quantum dot or the solvent that disperses thequantum dot.

Herein, the C1 to C20 alkoxy group may include a methoxy group, anethoxy group, an n-propoxy group, a isopropoxy group, an n-butoxy group,a isobutoxy group, a sec-butoxy group, a tert-butoxy group, an n-pentoxygroup, an isopentoxy group, a tert-pentoxy group, a neo pentoxy group, a1,2-dimethylpropoxy group, an n-hexyloxy group, an isohexyloxy group, a1,3-dimethylbutoxy group, a 1-isopropyl propoxy group, a1,2-dimethylbutoxy group, an n-heptyloxy group, a 1,4-dimethylpentyloxygroup, a 3-ethylpentyloxy group, a 2-methyl-1-isopropyl propoxy group, a1-ethyl-3-methylbutoxy group, an n-octyloxy group, a 2-ethylhexyloxygroup, a 3-methyl-1-isopropyl butoxy group, a 2-methyl-1-isopropoxygroup, a 1-tert-butyl-2-methylpropoxy group, an n-nonyloxy group, a3,5,5-trimethylhexyloxy group, an n-decyloxy group, a isodecyloxy group,an n-undecyloxy group, a 1-methyldecyloxy group, an n-dodecyloxy group,an n-tridecyloxy group, an n-tetradecyloxy group, an n-pentadecyloxygroup, an n-hexadecyloxy group, an n-heptadecyloxy group, ann-octadecyloxy group, an n-eicosyloxy group, and the like, but is notparticularly limited thereto.

The carbon number of the alkoxy group is more desirably in the followingtype.

For example, when the ligand of the quantum dot is a long chainalkyl-containing compound such as oleic acid, oleylamine, ortrioctylphosphine, the compound included in the hole transport layer mayalso desirably include a compound having a long chain alkoxy group. Thisis because the ligand of the quantum dot and the alkoxy group present inthe hole transport layer may interact with each other, thereby improvingeffects such as hole injectability.

In addition, when the solvent that disperses the quantum dot is along-chain hydrocarbon-based solvent, it is desirable that the number ofthe alkoxy group in the polymer compound is small in terms of securing aresidual film ratio of the hole transport layer.

Therefore, as the alkoxy group, a linear or branched C1 to C18 alkoxygroup is more desirable. These alkoxy groups may be appropriatelyselected according to the used quantum dot or the solvent that dispersesthe quantum dot.

Herein, the C6 to C60 monovalent aromatic hydrocarbon group and themonovalent aromatic heterocyclic group having 3 to 60 ring-forming atomsare the same as Ar₁ in Chemical Formula 2, except that the trivalentaromatic heterocyclic group and trivalent aromatic heterocyclic groupare changed into monovalent groups, and thus the descriptions thereofare omitted. In addition, when the C1 to C20 alkyl group, the C1 to C20alkoxy group, the C6 to C60 monovalent aromatic hydrocarbon group, orthe monovalent aromatic heterocyclic group having 3 to 60 ring-formingatoms is substituted, the substituent is the same as the substituent ofAr₁ in Chemical Formula 2, and thus the descriptions thereof areomitted.

Of these, R₁ and R₂ desirably are phenyl groups or fluorenyl groups.

a is the number of R₁ in Chemical Formula 2 bound to thenitrogen-containing aromatic heterocycle positioned in the side chain,but may be an integer ranging from 0 to 4.

b is the number of R₂ in Chemical Formula 2 bound to thenitrogen-containing aromatic heterocycle positioned in the side chain,but is an integer of 0 to 3, and desirably an integer of 0 to 2. Moredesirably it may be 0 or 1, particularly 0.

In Chemical Formula 2, Z₁ to Z₈ of the nitrogen-containing aromaticheterocycle may independently be a nitrogen atom or CH.

The nitrogen-containing aromatic heterocycle desirably has a structureshown below.

In the above chemical formula, * is a linking portion.

From the viewpoint of further improving the HOMO level and holetransport capability and reducing a driving voltage, X may desirably bestructural units represented by Chemical Formula 2-1 to Chemical Formula2-6. Herein, a plurality of X's in the segment of the alternatecopolymer of the structural unit represented by Chemical Formula 1 maybe the same or different.

In Chemical Formula 2-1 to Chemical Formula 2-6, Ar₄ is a substituted orunsubstituted C6 to C60 monovalent aromatic hydrocarbon group, or asubstituted or unsubstituted monovalent aromatic heterocyclic grouphaving 3 to 60 ring-forming atoms.

The specific example of X is shown below.

In the above chemical formulae, * is a linking portion, and “Alkyl”indicates substitution or unsubstitution with an alkyl group.

«Y»

The polymer compound 1 may include one type of Y or two or more types ofY as a structural unit.

The polymer compound 1 may improve solubility by including Y as astructural unit. For this reason, when the polymer compound 1 is used, athin film may be easily formed by a coating method.

In Chemical Formula 1, Y may be a substituted or unsubstituted C6 to C60divalent aromatic hydrocarbon group or a substituted or unsubstituteddivalent aromatic heterocyclic group having 3 to 60 ring-forming atoms.

Herein, the divalent aromatic hydrocarbon group and the divalentaromatic heterocyclic group are the same as Ar₁ in Chemical Formula 2,except that the trivalent aromatic heterocyclic group and the trivalentaromatic heterocyclic group are changed into divalent groups, and thusthe descriptions thereof are omitted.

Among them, from the viewpoint of improving solubility of the polymercompound 1, Y may desirably be a phenylene group, a fluorenediyl, abiphenylene group, a fluorenylene group, a naphthylene group, ananthracenylene group, a phenanthrylene group, a naphthacenylene group, apyrenylene group, a terphenylene group, a tolylene group, atert-butylphenylene group, or a (phenylpropyl)phenylene group, and moredesirably a phenylene group or a fluorenediyl group.

In addition, when the divalent aromatic hydrocarbon group or thedivalent aromatic heterocyclic group is substituted, the substituent isthe same as the substituent of Ar₁ in Chemical Formula 2, and thus thedescriptions thereof are omitted.

Among them, from the viewpoint of improving solubility of the polymercompound 1, the substituent may desirably be a C1 to C20 linear orbranched alkyl group.

The carbon number of the alkyl group is more desirably in the followingtype.

For example, when the ligand of the quantum dot is a long chainalkyl-containing compound such as oleic acid, oleylamine, ortrioctylphosphine, the compound included in the hole transport layer mayalso desirably include a compound having a long chain alkyl group. Thisis because the ligand of the quantum dot and the alkyl group present inthe hole transport layer may interact with each other, thereby improvingeffects such as hole injectability.

In addition, when the solvent that disperses the quantum dot is along-chain hydrocarbon-based solvent, it is desirable that the number ofthe alkyl group in the polymer compound is small in terms of securing aresidual film ratio of the hole transport layer.

Therefore, as the alkyl group, a linear or branched C1 to C18 alkylgroup is more desirable. The alkyl group may be appropriately selectedaccording to the used quantum dot or the solvent that disperses thequantum dot.

From the viewpoint of adjusting the HOMO level, Y may desirably be ofthe structural units represented by Chemical Formula 2-7 to ChemicalFormula 2-14. Herein, a plurality of Y's in the segment of the alternatecopolymer of the structural unit represented by Chemical Formula 1 maybe the same or different.

In Chemical Formula 2-7 to Chemical Formula 2-14, Ar₅₁ to Ar₅₅ areindependently a substituted or unsubstituted C6 to C60 monovalentaromatic hydrocarbon group, a substituted or unsubstituted monovalentaromatic heterocyclic group having 3 to 60 ring-forming atoms, C1 to C20alkyl group, or a hydrogen atom,

A₁₁ to A₁₃ are independently —O—, —S—, —Se—, —CR₃R₄—, —SiR₃R₄— (R₃ andR₄ are independently a hydrogen atom, a deuterium atom, a substituted orunsubstituted alkyl group, a substituted or unsubstituted aryl group, ora substituted or unsubstituted heteroaryl group),

A₂₁ to A₂₈ are independently —CR₅═, —N═, —SiR₅═ (R₅ is hydrogen, adeuterium atom, a substituted or unsubstituted alkyl group, asubstituted or unsubstituted aryl group, or a substituted orunsubstituted heteroaryl group.

The carbon number of the alkyl group is more desirably in the followingtype.

For example, when the ligand of the quantum dot is a long chainalkyl-containing compound such as oleic acid, oleylamine, ortrioctylphosphine, the compound included in the hole transport layer mayalso desirably include a compound having a long chain alkyl group. Thisis because the ligand of the quantum dot and the alkyl group present inthe hole transport layer may interact with each other, thereby improvingeffects such as hole injectability.

In addition, when the solvent that disperses the quantum dot is along-chain hydrocarbon-based solvent, it is desirable that the number ofthe alkyl group in the polymer compound is small in terms of securing aresidual film ratio of the hole transport layer.

Therefore, as the alkyl group, a linear or branched C1 to C18 alkylgroup is more desirable. The alkyl group may be appropriately selectedaccording to the used quantum dot or the solvent that disperses thequantum dot.

The specific examples of Y are shown below.

In the above chemical formulae, A is O, S, or Se, and when two or moreX's exist, a plurality of X's may be same or different. In addition, *is a linking portion, and “Alkyl” indicates substitution with an alkylgroup.

The polymer compound 1 is desirably represented by Chemical Formula 3.As a result, the light emitting life-span of the quantum dot lightemitting device is lengthened.

In Chemical Formula 3, E is a substituted or unsubstituted C6 to C60monovalent aromatic hydrocarbon group, or a substituted or unsubstitutedmonovalent aromatic heterocyclic group having 3 to 60 ring-formingatoms, m is an integer of 2 or more, and a plurality of X's and Y's mayindependently be the same or different.

Herein, the monovalent aromatic hydrocarbon group and the monovalentaromatic heterocyclic group are the same as Ar₁ in Chemical Formula 2,except that the trivalent aromatic heterocyclic group and the trivalentaromatic heterocyclic group are changed into divalent groups, and thusthe descriptions thereof are omitted. In addition, when the monovalentaromatic hydrocarbon group or the monovalent aromatic heterocyclic groupis substituted, the substituent is the same as the substituent of Ar₁ inChemical Formula 2, and thus the descriptions thereof are omitted.

The specific example of E (end group) of Chemical Formula 3 is shownbelow. As an example of E, a group of the following cross-linking groupsis desirable.

In the cross-linking groups,

R₁₀ to R₁₆ are independently a hydrogen atom, or a substituted orunsubstituted C1 to C10 alkyl group, and p is an integer of 1 to 10.

Moreover, the following groups are desirable as an example of E.

In the above chemical formulae, * is a linking portion.

Although the polymer compound 1 may be used as a material forelectroluminescent (EL) devices, it is particularly effective to use asa hole transporting material for EL devices including quantum dots.

Synthesis Method of Polymer Compound 1

The polymer compound 1 may be suitably synthesized by combiningwell-known organic synthesis reactions. Specific synthesis method of thepolymer compound 1 may be easily understood by a person of an ordinaryskill in the art referring to the following examples. Specifically, thepolymer compound 1 may be synthesized by copolymerizing at least onemonomer 1 represented by Chemical Formula 4 and at least one monomer 2represented by Chemical Formula 5 at a mole ratio of about 1:1. Themonomer 1 and monomer 2 may be suitably synthesized by combiningwell-known organic synthesis reaction. In addition, the monomer 1 andmonomer 2 may be identified using a well-known analysis method (forexample, NMR, LC-MS).

In Chemical Formula 4 and Chemical Formula 5, Ar₁, Ar₂, Ar₃, L₁, L₂, R₁,R₂, a, and b are the same as in Chemical Formula 2. W₁ to W₄ areindependently a halogen atom (a fluorine atom, a chlorine atom, abromine atom, an iodine atom, particularly a bromine atom) or thefollowing groups.

In the above chemical formulae, R_(A) to R_(D) are independently C1 toC3 alkyl group.

Polymer Compound 2

According to the preferred embodiment of the present disclosure, thepolymer material includes a polymer compound (hereinafter, simplyreferred to as “polymer compound 2”) including a repeating unitrepresented by Chemical Formula P-2. According to a more preferredembodiment, the polymer material may be the polymer compound 2.

The polymer compound 2 is a compound including a repeating unitrepresented by Chemical Formula P-2.

In Chemical Formula P-2,

R₁, R₂, and R₃ are independently a hydrogen atom, a substituted orunsubstituted C1 to C10 alkyl group, or a substituted or unsubstitutedring-forming C6 to C30 aryl group,

m is an integer of 1 to 20,

F and F′ are independently a divalent group having a fluorene structureincluding aza-fluorene, and

A is a divalent group represented by Chemical Formula (P-21),

wherein, in Chemical Formula (P-21),

L₁ and L₂ are independently a single bond, a substituted orunsubstituted C1 to C20 alkylene group, a substituted or unsubstitutedring-forming C3 to C16 cycloalkylene group, a substituted orunsubstituted ring-forming C6 to C30 arylene group, a substituted orunsubstituted C1 to C20 oxyalkylene group, a substituted orunsubstituted ring-forming C3 to C16 oxycycloalkylene group, asubstituted or unsubstituted ring-forming C6 to C30 oxyarylene group, asubstituted or unsubstituted C7 to C40 aralkylene group, a substitutedor unsubstituted ring-forming C5 to C30 heteroarylene group, asubstituted or unsubstituted C1 to C20 aminoalkylene group, asubstituted or unsubstituted ring-forming C6 to C30 aminoarylene group,or a silylene group substituted with an alkyl group or an aryl group,

Ar₁ is hydrogen, a substituted or unsubstituted C1 to C20 alkyl group, asubstituted or unsubstituted ring-forming C3 to C16 cycloalkyl group, asubstituted or unsubstituted ring-forming C6 to C30 aryl group, asubstituted or unsubstituted C1 to C20 alkoxy group, a substituted orunsubstituted ring-forming C3 to C16 cycloalkoxy group, a substituted orunsubstituted ring-forming C6 to C30 aryloxy group, a substituted orunsubstituted C7 to C40 aralkyl group, a substituted or unsubstitutedring-forming C5 to C30 heteroaryl group, an alkylamino group including asubstituted or unsubstituted C1 to C20 alkyl group, a substituted orunsubstituted ring-forming C6 to C30 arylamino group, or a cyclicsubstituent formed by linking these substituents with L₁ or L₂,

** is a linking portion with another substituent, and

R₄ is hydrogen, a halogen atom, a hydroxy group, an amino group, a nitrogroup, a cyano group, a substituted or unsubstituted silyl group, asubstituted or unsubstituted C1 to C20 alkyl group, a substituted orunsubstituted ring-forming C3 to C16 cycloalkyl group, a substituted orunsubstituted ring-forming C6 to C30 aryl group, a substituted orunsubstituted C1 to C20 alkoxy group, a substituted or unsubstitutedring-forming C3 to C16 cycloalkoxy group, a substituted or unsubstitutedring-forming C6 to C30 aryloxy group, a substituted or unsubstituted C7to C40 aralkyl group, a substituted or unsubstituted ring-forming C5 toC30 heteroaryl group, an alkylamino group including a substituted orunsubstituted C1 to C20 alkyl group, or a substituted or unsubstitutedring-forming C6 to C30 arylamino group.

The carbon number of the alkyl group is more desirably in the followingtype.

For example, when the ligand of the quantum dot is a long chainalkyl-containing compound such as oleic acid, oleylamine, ortrioctylphosphine, the compound included in the hole transport layer mayalso desirably include a compound having a long chain alkyl group. Thisis because the ligand of the quantum dot and the alkyl group present inthe hole transport layer may interact with each other, thereby improvingeffects such as hole injectability.

In addition, when the solvent that disperses the quantum dot is along-chain hydrocarbon-based solvent, it is desirable that the number ofthe alkyl group in the polymer compound is small in terms of securing aresidual film ratio of the hole transport layer.

Therefore, as the alkyl group, a linear or branched C1 to C18 alkylgroup is more desirable. The alkyl group may be appropriately selectedaccording to the used quantum dot or the solvent that disperses thequantum dot.

In addition, the carbon number of the alkoxy group is more desirably inthe following type.

For example, when the ligand of the quantum dot is a long chainalkyl-containing compound such as oleic acid, oleylamine, ortrioctylphosphine, the compound included in the hole transport layer mayalso desirably include a compound having a long chain alkoxy group. Thisis because the ligand of the quantum dot and the alkoxy group present inthe hole transport layer may interact with each other, thereby improvingeffects such as hole injectability.

In addition, when the solvent that disperses the quantum dot is along-chain hydrocarbon-based solvent, it is desirable that the number ofthe alkoxy group in the polymer compound is small in terms of securing aresidual film ratio of the hole transport layer.

Therefore, as the alkoxy group, a linear or branched C1 to C18 alkoxygroup is more desirable. These alkoxy groups may be appropriatelyselected according to the used quantum dot or the solvent that dispersesthe quantum dot.

Specifically, the substituent represented by F and F′ may independentlybe represented by Chemical Formula (P-22).

In Chemical Formula (P-22), R₅ to R₈ are independently hydrogen atom, ahalogen atom, a hydroxy group, an amino group, a nitro group, a cyanogroup, a substituted or unsubstituted silyl group, a substituted orunsubstituted C1 to C20 alkyl group, a substituted or unsubstitutedring-forming C3 to C16 cycloalkyl group, a substituted or unsubstitutedring-forming C6 to C30 aryl group, a substituted or unsubstituted C1 toC20 alkoxy group, a substituted or unsubstituted ring-forming C3 to C16cycloalkoxy group, a substituted or unsubstituted ring-forming C6 to C30aryloxy group, a substituted or unsubstituted C7 to C40 aralkyl group, asubstituted or unsubstituted ring-forming C5 to C30 heteroaryl group, asubstituted or unsubstituted C1 to C20 alkylamino group, a substitutedor unsubstituted ring-forming C6 to C30 arylamino group, or a cyclicsubstituent formed by linking adjacent groups of these substituent,

a and b are independently an integer of 1 to 4, and

Y₁ to Y₈ are independently one of a carbon atom or a nitrogen atom.

The linking portion of the substituent represented by Chemical Formula(P-22) and another substituent of the main chain, A and R₄, and the likemay be arbitrary and may be bound at any one substitution position.

The carbon number of the alkyl group is more desirably in the followingtype.

For example, when the ligand of the quantum dot is a long chainalkyl-containing compound such as oleic acid, oleylamine, ortrioctylphosphine, the compound included in the hole transport layer mayalso desirably include a compound having a long chain alkyl group. Thisis because the ligand of the quantum dot and the alkyl group present inthe hole transport layer may interact with each other, thereby improvingeffects such as hole injectability.

In addition, when the solvent that disperses the quantum dot is along-chain hydrocarbon-based solvent, it is desirable that the number ofthe alkyl group in the polymer compound is small in terms of securing aresidual film ratio of the hole transport layer.

Therefore, as the alkyl group, a linear or branched C1 to C18 alkylgroup is more desirable. The alkyl group may be appropriately selectedaccording to the used quantum dot or the solvent that disperses thequantum dot.

In addition, the carbon number of the alkoxy group is more desirably inthe following type.

For example, when the ligand of the quantum dot is a long chainalkyl-containing compound such as oleic acid, oleylamine, ortrioctylphosphine, the compound included in the hole transport layer mayalso desirably include a compound having a long chain alkoxy group. Thisis because the ligand of the quantum dot and the alkoxy group present inthe hole transport layer may interact with each other, thereby improvingeffects such as hole injectability.

In addition, when the solvent that disperses the quantum dot is along-chain hydrocarbon-based solvent, it is desirable that the number ofthe alkoxy group in the polymer compound is small in terms of securing aresidual film ratio of the hole transport layer.

Therefore, as the alkoxy group, a linear or branched C1 to C18 alkoxygroup is more desirable. These alkoxy groups may be appropriatelyselected according to the used quantum dot or the solvent that dispersesthe quantum dot.

More specifically, the substituent represented by Chemical Formula(P-22) may be any substituted or unsubstituted substituent of thefollowing substituent groups.

The substituent represented by Chemical Formula (P-21) may be forexample, an aliphatic amino group or an aromatic amino group, or mayform a cyclic structure in which Ar₁ and L₁ or L₂ are linked to eachother.

In addition, in Chemical Formula (P-21), L₁ and L₂ may be a substitutedor unsubstituted fluorenylene group, a substituted or unsubstitutedaminoalkylene group, or a substituted or unsubstituted aminoarylenegroup. That is, the polymer compound 2 according to the presentembodiment may have a structure in which a substituent having a fluorenestructure and a substituent having an amine structure are alternatelybonded, or a structure in which a substituent having a fluorenestructure or an amine structure is continuously bonded.

Since the fluorene structure is directly bound to the side chain portionof the polymer, the polymer compound 2 having the aforementionedstructure has high bond dissociation energy between carbons of thepolymer, and high current flow durability and electron resistance.Accordingly, the quantum dot EL device using the polymer compound 2according to the present embodiment may improve light emittinglife-span.

Here, specific examples of structural units (repeating units) of thepolymer compound 2 according to the present embodiment are as follows.However, the structural units of the polymer compound 2 are not limitedto the structures illustrated below. m may be for example, an integer of1 to 10.

In addition, the polymer compound 2 according to the present embodimentis more desirably a copolymer formed by copolymerization with apolymerizable comonomer (comonomer) having at least one cross-linkinggroup. The cross-linking group of the polymerizable comonomer isspecifically a cross-linking group of the following cross-linkinggroups.

In the cross-linking groups,

R₁₀ to R₁₆ are independently a hydrogen atom, or a substituted orunsubstituted C1 to C10 alkyl group, and p is an integer of 1 to 10.

When the polymer compound 2 according to the present embodiment is thecopolymer with the polymerizable comonomer having the cross-linkinggroup, the polymer compound 2 may form an insoluble film in a solvent bybeing cross-linked by heat or the like after film formation. Thereby,the polymer compound 2 according to the present embodiment may suppressdissolution and mixing of the materials between the laminated layers,and thus it easier to form a laminate structure.

A ratio of the polymerizable comonomer having the cross-linking groupmay be desirably greater than or equal to about 1 mole percent (mol %)and less than or equal to about 50 mol % based on a total amount of theentire monomers forming the polymer compound 2. Within this range, afilm insoluble in a solvent may be formed by a cross-linking reaction.In addition, the effect of improving the light emitting life-span in thequantum dot EL device is increased. The ratio of the polymerizablecomonomer having the cross-linking group may be desirably greater thanor equal to about 5 mol % and less than or equal to about 15 mol %, andmore desirably about 10 mol % based on a total amount of the entiremonomers forming the polymer compound 2.

Here, the polymerizable comonomer having the cross-linking group is moredesirably specifically a compound represented by Chemical Formula P-23.

In Chemical Formula P-23,

R₁₇, R1₈, and R₁₉ are independently hydrogen atom, a substituted orunsubstituted C1 to C10 alkyl group, or a substituted or unsubstitutedring-forming C6 to C30 aryl group,

R₂₀, R₂₁, R₂₂, R₂₃, and R₂₄ are independently hydrogen atom, a halogenatom, a hydroxy group, an amino group, a nitro group, a cyano group, asubstituted or unsubstituted silyl group, a substituted or unsubstitutedC1 to C20 alkyl group, a substituted or unsubstituted ring-forming C3 toC16 cycloalkyl group, a substituted or unsubstituted ring-forming C6 toC30 aryl group, a substituted or unsubstituted C1 to C20 alkoxy group, asubstituted or unsubstituted cyclic C3 to C16 cycloalkoxy group, asubstituted or unsubstituted ring-forming C6 to C30 aryloxy group, asubstituted or unsubstituted C7 to C40 aralkyl group, a substituted orunsubstituted ring-forming C5 to C30 heteroaryl group, an alkylaminogroup having a substituted or unsubstituted C1 to C20 alkyl group, or asubstituted or unsubstituted ring-forming C6 to C30 arylamino group, ora cyclic substituent formed by linking adjacent substituents to eachother,

L₃ is a single bond, a substituted or unsubstituted C1 to C20 alkylenegroup, a substituted or unsubstituted ring-forming C3 to C16cycloalkylene group, a substituted or unsubstituted ring-forming C6 toC30 arylene group, a substituted or unsubstituted C1 to C20 oxyalkylenegroup, a substituted or unsubstituted ring-forming C3 to C16oxycycloalkylene group, a substituted or unsubstituted ring-forming C6to C30 oxy arylene group, a substituted or unsubstituted C7 to C40aralkylene group, a substituted or unsubstituted ring-forming C5 to C30heteroarylene group, a substituted or unsubstituted C1 to C20aminoalkylene group, a substituted or unsubstituted ring-forming C6 toC30 aminoarylene group, or a silylene group substituted with an alkylgroup or an aryl group, and

at least one of R₂₀, R₂₁, R₂₂, or R₂₃ R₂₄ is a cross-linking group ofthe above cross-linking groups.

The carbon number of the alkyl group is more desirably in the followingtype.

For example, when the ligand of the quantum dot is a long chainalkyl-containing compound such as oleic acid, oleylamine, ortrioctylphosphine, the compound included in the hole transport layer mayalso desirably include a compound having a long chain alkyl group. Thisis because the ligand of the quantum dot and the alkyl group present inthe hole transport layer may interact with each other, thereby improvingeffects such as hole injectability.

In addition, when the solvent that disperses the quantum dot is along-chain hydrocarbon-based solvent, it is desirable that the number ofthe alkyl group in the polymer compound is small in terms of securing aresidual film ratio of the hole transport layer.

Therefore, as the alkyl group, a linear or branched C1 to C18 alkylgroup is more desirable. The alkyl group may be appropriately selectedaccording to the used quantum dot or the solvent that disperses thequantum dot.

The carbon number of the alkoxy group is more desirably in the followingtype.

For example, when the ligand of the quantum dot is a long chainalkyl-containing compound such as oleic acid, oleylamine, ortrioctylphosphine, the compound included in the hole transport layer mayalso desirably include a compound having a long chain alkoxy group. Thisis because the ligand of the quantum dot and the alkoxy group present inthe hole transport layer may interact with each other, thereby improvingeffects such as hole injectability.

In addition, when the solvent that disperses the quantum dot is along-chain hydrocarbon-based solvent, it is desirable that the number ofthe alkoxy group in the polymer compound is small in terms of securing aresidual film ratio of the hole transport layer.

Therefore, as the alkoxy group, a linear or branched C1 to C18 alkoxygroup is more desirable. These alkoxy groups may be appropriatelyselected according to the used quantum dot or the solvent that dispersesthe quantum dot.

In addition, L₃ may specifically be a substituent represented byChemical Formula P-24 or a substituent represented by Chemical Formula(P-21).

In Chemical Formula P-24,

A′ is a substituent represented by the above General Formula P-21,

F″ is a substituent represented by the above General Formula P-22,

q is an integer of 1 to 20, and

* is a linking portion with substituted fluorenylene group by R₂₀ andR₂₁.

When L₃ is a substituent represented by Chemical Formula P-24 orChemical Formula (P-21), the polymerizable comonomer having thecross-linking group may have the same structure as the structurerepresented by Chemical Formula P-2. As a result, the polymer compound 2according to the present embodiment may further improve the lightemitting life-span of the quantum dot EL device.

Here, the specific example of the structural unit (repeating unit)corresponding to a polymerizable copolymer having at least onecross-linking group is shown below. However, the structural unitscorresponding to the polymerizable copolymer having at least onecross-linking group are not limited to the following structures.Hereinafter, m and n may be for example, an integer of 1 to 10.

As described above, the polymer compound 2 according to the presentembodiment may improve the light emitting life-span of the quantum dotEL device. In addition, the polymer compound 2 according to the presentembodiment may also improve a coating film stability by forming thecopolymer with the polymerizable comonomer having the cross-linkinggroup. Therefore, it is possible to improve light emittingcharacteristics and stability when the quantum dot EL device is formedby the laminate structure.

Polymer Compound 3

According to a preferred embodiment of the present invention, thepolymer material may include a polymer compound represented by ChemicalFormula I or Chemical Formula I′ (hereinafter also referred to as“polymer compound 3”). In a more preferred embodiment, the polymermaterial is polymer compound 3.

1. Definition and Explanation of Terminologies

Before describing the details of the embodiments, some terminologies aredefined or explained.

When used in the present embodiment, the term “alkyl” may be, forexample, a branched and linear saturated aliphatic hydrocarbon group.Unless specifically stated, the term is also intended to include cyclicgroups. Examples of the alkyl group may be methyl, ethyl, propyl,isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, isopentyl,neopentyl, cyclopentyl, hexyl, cyclohexyl, isohexyl, and the like. Asthe term “alkyl”, both substituted and unsubstituted hydrocarbon groupsmay also be mentioned. In some embodiments, the alkyl group may bemono-, di-, and tri-substituted group. One example of a substitutedalkyl group is trifluoromethyl. In addition, the other substituted alkylgroup is formed of one or a plurality of substituents described in thepresent embodiment. In some embodiments, the alkyl group has 1 to 20carbon atoms. In other embodiments, this group has 1 to 6 carbon atoms.The term is intended to include heteroalkyl groups. The heteroalkylgroup may have from 1 to 20 carbon atoms.

The term “aryl” means an aromatic carbon ring moiety which may bemonocycle or polycycle (bicycle or higher) condensed to each other orlinked to each other by a covalent bond. Any desirably ring position ofthe aryl moiety may be linked by a covalent bond to the defined chemicalstructure. Examples of the aryl moiety include phenyl, 1-naphthyl,2-naphthyl, dihydronaphthyl, tetrahydronaphthyl, biphenyl, anthryl,phenanthryl, fluorenyl, indanyl, biphenylenyl, acenaphthenyl,acenaphthylenyl, and the like, but are not limited to. In someembodiments, the aryl group may have 6 to 60 carbon atoms; in someembodiments, may have 6 to 30 carbon atoms. The term is intended toinclude heteroaryl groups. The heteroaryl group may include 4 to 50carbon atoms; in some embodiments, 4 to 30 carbon atoms.

The term “alkoxy” is intended to mean the group —OR (wherein, R isalkyl).

The term aryloxy is intended to mean the group —OR (wherein, R is aryl).

Unless specifically mentioned, all groups may be substituted orunsubstituted.

When referring to a layer, material, member, or structure, the term“charge transport” means that such a layer, material, member, orstructure promotes transport of charge through the thickness of themember, member, or structure relatively efficiently and with a smallcharge loss. A hole transporting material promotes positive charges; anelectron transporting material promotes negative charges. The lightemitting material may also have several charge transportcharacteristics, but the term “charge transport layer, material, member,or structure” is not intended to include a layer, material, member, orstructure whose main function is light emitting.

The term “compound” is a non-charged material composed of molecules thatfurther include an atom, and means a material that cannot separate atomsfrom their molecules by physical means without destroying the chemicalbond. The term is intended to include oligomers and polymers.

The term “cross-linking group” or “cross-linking group” is intended tomean a group capable of causing cross-linking by exposure to heattreatment or radiation. In some embodiments, radiation is UV or visiblelight.

The prefix “fluoro” is intended to indicate that one of the groups or aplurality of hydrogens is replaced by fluorine.

The prefix “hetero” represents one or a plurality of carbon atomsreplaced by another atom. In some embodiments, the heteroatom may be O,N, S, or a combination thereof.

The term “silyl” refers to the group R₃Si— (wherein, R is H, D, C1 toC20 alkyl, fluoroalkyl, or aryl). In some embodiments, one or aplurality of carbons of the R alkyl groups is substituted with Si. Insome embodiments, the silyl group is (hexyl)₂Si(Me)CH₂CH₂Si(Me)₂- and[CF₃(CF₂)₆CH₂CH₂]₂SiMe-.

The term “siloxane” means the group (RO)₃Si— (wherein, R is H, D, C1 toC20 alkyl, or fluoroalkyl).

The polymer compound 3 has Chemical Formula I or Chemical Formula I′:

In Chemical Formula I or Chemical Formula I′:

Ar¹ and Ar² are the same or different and an aryl group;

R¹ to R⁵ are independently the same or different and are D, F, alkyl,aryl, alkoxy, silyl, or a cross-linking group;

R⁶ is the same or different and is H, D, or a halogen;

a, b, c, d, and e are independently an integer of 0 to 4;

f is 1 or 2;

g is 0, 1, or 2;

h is 1 or 2; and

n is an integer of greater than 0.

The carbon number of the alkyl group is more desirably in the followingtype.

For example, when the ligand of the quantum dot is a long chainalkyl-containing compound such as oleic acid, oleylamine, ortrioctylphosphine, the compound included in the hole transport layer mayalso desirably include a compound having a long chain alkyl group. Thisis because the ligand of the quantum dot and the alkyl group present inthe hole transport layer may interact with each other, thereby improvingeffects such as hole injectability.

In addition, when the solvent that disperses the quantum dot is along-chain hydrocarbon-based solvent, it is desirable that the number ofthe alkyl group in the polymer compound is small in terms of securing aresidual film ratio of the hole transport layer.

Therefore, as the alkyl group, a linear or branched C1 to C18 alkylgroup is more desirable. The alkyl group may be appropriately selectedaccording to the used quantum dot or the solvent that disperses thequantum dot.

The carbon number of the alkoxy group is more desirably in the followingtype.

For example, when the ligand of the quantum dot is a long chainalkyl-containing compound such as oleic acid, oleylamine, ortrioctylphosphine, the compound included in the hole transport layer mayalso desirably include a compound having a long chain alkoxy group. Thisis because the ligand of the quantum dot and the alkoxy group present inthe hole transport layer may interact with each other, thereby improvingeffects such as hole injectability.

In addition, when the solvent that disperses the quantum dot is along-chain hydrocarbon-based solvent, it is desirable that the number ofthe alkoxy group in the polymer compound is small in terms of securing aresidual film ratio of the hole transport layer.

Therefore, as the alkoxy group, a linear or branched C1 to C18 alkoxygroup is more desirable. These alkoxy groups may be appropriatelyselected according to the used quantum dot or the solvent that dispersesthe quantum dot.

In some embodiments, n=1 and R⁶ is a halogen. Such a polymer compound 3may be useful as a monomer for the formation of a polymer compound. Insome embodiments, the halogen is Cl or Br; in some embodiments, Br.

In some embodiments, n=1 and R⁶ is H or D.

In some embodiments, the polymer compound 3 having Chemical Formula I orChemical Formula I′ may be deuterated. The term “deuterated” is intendedto mean that at least one H is replaced by D. The term “deuteratedanalog” refers to a structure analog of any compound or group in whichone or a plurality of available hydrogens are replaced by deuterium. Inthe deuterated compounds or deuterated analogs, the deuterium is atleast 100 times the natural presence level. In some embodiments, thepolymer compound 3 is at least 10% deuterated. “% deuterated” or “%deuteration” means a ratio of deuteron relative to a sum of proton anddeuteron, expressed as a percentage. In some embodiments, the polymercompound 3 may be at least 20% deuterated; in some embodiments, it maybe at least 30% deuterated; in some embodiments, it may be at least 40%deuterated; in some embodiments, it may be at least 50% deuterated; insome embodiments, it may be at least 60% deuterated; in someembodiments, it may be at least 70% deuterated; in some embodiments, itmay be at least 80% deuterated; in some embodiments, it may be at least90% deuterated; and in some embodiments, it may be 100% deuterated.

The deuterated material may be difficult to be decomposed by a hole, anelectron, an exciton, or a combination thereof. Deuteration maypotentially prevent degradation of compounds during device operation,which may lead to an improvement in device life-span. In general, thisimprovement is achieved without sacrificing other devicecharacteristics. In addition, deuterated compounds frequently havegreater air resistance than non-deuterated analogs. This may result ingreater process resistance both in the preparation and purification ofmaterials and in the formation of electronic devices using thesematerials.

In some embodiments, the polymer compound 3 of Chemical Formula I orChemical Formula I′ may have Chemical Formula Ia,

wherein, R¹ to R⁶, Ar¹, Ar², a to h, and n are the same as defined inChemical Formula I.

In some embodiments, Ar¹ and Ar² are aryl groups having no condensedring. In some embodiments, Ar¹ and Ar² has Chemical Formula a,

wherein:

R⁷ is the same or different and is D, alkyl, alkoxy, siloxane, andsilyl;

i is the same or different and is an integer of 1 to 4;

j is an integer of 0 to 5; and

m is an integer of 1 to 5.

The carbon number of the alkyl group is more desirably in the followingtype.

For example, when the ligand of the quantum dot is a long chainalkyl-containing compound such as oleic acid, oleylamine, ortrioctylphosphine, the compound included in the hole transport layer mayalso desirably include a compound having a long chain alkyl group. Thisis because the ligand of the quantum dot and the alkyl group present inthe hole transport layer may interact with each other, thereby improvingeffects such as hole injectability.

In addition, when the solvent that disperses the quantum dot is along-chain hydrocarbon-based solvent, it is desirable that the number ofthe alkyl group in the polymer compound is small in terms of securing aresidual film ratio of the hole transport layer.

Therefore, as the alkyl group, a linear or branched C1 to C18 alkylgroup is more desirable. The alkyl group may be appropriately selectedaccording to the used quantum dot or the solvent that disperses thequantum dot.

The carbon number of the alkoxy group is more desirably in the followingtype.

For example, when the ligand of the quantum dot is a long chainalkyl-containing compound such as oleic acid, oleylamine, ortrioctylphosphine, the compound included in the hole transport layer mayalso desirably include a compound having a long chain alkoxy group. Thisis because the ligand of the quantum dot and the alkoxy group present inthe hole transport layer may interact with each other, thereby improvingeffects such as hole injectability.

In addition, when the solvent that disperses the quantum dot is along-chain hydrocarbon-based solvent, it is desirable that the number ofthe alkoxy group in the polymer compound is small in terms of securing aresidual film ratio of the hole transport layer.

Therefore, as the alkoxy group, a linear or branched C1 to C18 alkoxygroup is more desirable. These alkoxy groups may be appropriatelyselected according to the used quantum dot or the solvent that dispersesthe quantum dot.

In some embodiments, Ar¹ and Ar² may have Chemical Formula b,

wherein:

R⁷ is the same or different and is D, alkyl, alkoxy, siloxane, andsilyl;

i is the same or different and is an integer of 1 to 4;

j is an integer of 0 to 5; and

m is an integer of 1 to 5.

The carbon number of the alkyl group is more desirably in the followingtype.

For example, when the ligand of the quantum dot is a long chainalkyl-containing compound such as oleic acid, oleylamine, ortrioctylphosphine, the compound included in the hole transport layer mayalso desirably include a compound having a long chain alkyl group. Thisis because the ligand of the quantum dot and the alkyl group present inthe hole transport layer may interact with each other, thereby improvingeffects such as hole injectability.

In addition, when the solvent that disperses the quantum dot is along-chain hydrocarbon-based solvent, it is desirable that the number ofthe alkyl group in the polymer compound is small in terms of securing aresidual film ratio of the hole transport layer.

Therefore, as the alkyl group, a linear or branched C1 to C18 alkylgroup is more desirable. The alkyl group may be appropriately selectedaccording to the used quantum dot or the solvent that disperses thequantum dot.

The carbon number of the alkoxy group is more desirably in the followingtype.

For example, when the ligand of the quantum dot is a long chainalkyl-containing compound such as oleic acid, oleylamine, ortrioctylphosphine, the compound included in the hole transport layer mayalso desirably include a compound having a long chain alkoxy group. Thisis because the ligand of the quantum dot and the alkoxy group present inthe hole transport layer may interact with each other, thereby improvingeffects such as hole injectability.

In addition, when the solvent that disperses the quantum dot is along-chain hydrocarbon-based solvent, it is desirable that the number ofthe alkoxy group in the polymer compound is small in terms of securing aresidual film ratio of the hole transport layer.

Therefore, as the alkoxy group, a linear or branched C1 to C18 alkoxygroup is more desirable. These alkoxy groups may be appropriatelyselected according to the used quantum dot or the solvent that dispersesthe quantum dot.

In an embodiment having Chemical Formulae a and b, at least one of i andj is not zero. In some embodiments, m=1 to 3.

In some embodiments, Ar¹ and Ar² are phenyl, biphenyl, terphenyl,deuterated derivatives thereof, and derivatives thereof having one ormore substituents such as alkyl, alkoxy, silyl, or cross-linking groups.

In some embodiments, R¹ to R⁵ are D or C1 to C10 alkyl. In someembodiments, the alkyl group may be deuterated.

In some embodiments, a=e=0. In some embodiments, a=e=4 and R¹ and R⁵ areD.

In some embodiments, b>0 and at least one R² is alkyl. In someembodiments, the alkyl group may be deuterated. In some embodiments, b=4and one R² is alkyl and the remainder is D.

In some embodiments, c>0 and at least one R³ is alkyl. In someembodiments, the alkyl group may be deuterated. In some embodiments, c=4and one R³ is alkyl and the remainder is D.

In some embodiments, c=4, two R³'s are alkyl and two R³'s are D.

In some embodiments, d>0 and at least one R⁴ is alkyl. In someembodiments, the alkyl group may be deuterated. In some embodiments,d=4, one R⁴ is alkyl and the remainder is D.

In some embodiments, f=h=2.

In some embodiments, g=1.

The carbon number of the alkyl group is more desirably in the followingtype.

For example, when the ligand of the quantum dot is a long chainalkyl-containing compound such as oleic acid, oleylamine, ortrioctylphosphine, the compound included in the hole transport layer mayalso desirably include a compound having a long chain alkyl group. Thisis because the ligand of the quantum dot and the alkyl group present inthe hole transport layer may interact with each other, thereby improvingeffects such as hole injectability.

In addition, when the solvent that disperses the quantum dot is along-chain hydrocarbon-based solvent, it is desirable that the number ofthe alkyl group in the polymer compound is small in terms of securing aresidual film ratio of the hole transport layer.

Therefore, as the alkyl group, a linear or branched C1 to C18 alkylgroup is more desirable. The alkyl group may be appropriately selectedaccording to the used quantum dot or the solvent that disperses thequantum dot.

The carbon number of the alkoxy group is more desirably in the followingtype.

For example, when the ligand of the quantum dot is a long chainalkyl-containing compound such as oleic acid, oleylamine, ortrioctylphosphine, the compound included in the hole transport layer mayalso desirably include a compound having a long chain alkoxy group. Thisis because the ligand of the quantum dot and the alkoxy group present inthe hole transport layer may interact with each other, thereby improvingeffects such as hole injectability.

In addition, when the solvent that disperses the quantum dot is along-chain hydrocarbon-based solvent, it is desirable that the number ofthe alkoxy group in the polymer compound is small in terms of securing aresidual film ratio of the hole transport layer.

Therefore, as the alkoxy group, a linear or branched C1 to C18 alkoxygroup is more desirable. These alkoxy groups may be appropriatelyselected according to the used quantum dot or the solvent that dispersesthe quantum dot.

In some embodiments, the polymer compound 3 having Chemical Formula I orChemical Formula I′ has high triplet energy. The term “triplet energy”means the lowest excitation triplet state of a material as an eV unit.The triplet energy is reported as a positive number and represents theenergy of the triplet state with respect to the ground state, usuallythe singlet state. The light emitting organic metal material emits lightfrom an exited state having mixed singlet and triplet characteristics,and is referred to as “phosphorescence” in the present embodiment. Whenan organic metal phosphorescent material is used in the light emittinglayer, the presence of a material having a low triplet energy causesquenching of energy phosphorescent radiation exceeding 2.0 eV. Thisleads to deteriorated efficiency. The quenching may occur when amaterial such as a host material, and the like, are in anelectroluminescent layer, or in a layer adjacent to theelectroluminescent layer such as a hole transport layer, and the like.In some embodiments, a material having Chemical Formula I or ChemicalFormula I′ has a triplet energy level greater than about 2.1 eV; in someembodiments, it has a triplet energy level greater than about 2.2 eV; insome embodiments, it has a triplet energy level greater than about 2.45eV; and in some embodiments, it has a triplet energy level greater thanabout 2.6 eV. The triplet energy may be calculated deductively, or maybe measured using pulse radiation decomposition or low temperatureluminescence spectroscopy, or either.

Some non-limiting examples of the polymer compound 3 having ChemicalFormula I or Chemical Formula I′ include the following compounds R toEE.

The polymer compound 3 may be prepared using any technique that producesC—C or C—N bonds. Various techniques such as Suzuki, Yamamoto, Stille,and Pd- or Ni-catalyzed C—N coupling, and the like are known. Thedeuterated compound may be prepared in a similar manner using adeuterated precursor material or may be more generally prepared bytreating a non-deuterated compound with a deuterated solvent such asd6-benzene under the presence of a Lewis acid H/D exchange catalyst,such as aluminum trichloride or ethyl aluminum dichloride, and the like.

The polymer compound 3 of the present embodiment may be used as a holetransporting material, as an electroluminescent material and as a hostfor an electroluminescent material. This polymer compound 3 has similarhole mobility and HOMO/LUMO energy as the efficient small molecular holetransport compound such as N, N′-diphenyl-N, N′-bis(3-methylphenyl)-[1,1′-biphenyl]-4,4′-diamine (TPD)

The compound such as TPD should be generally applied using depositiontechniques.

Polymer Compound 4

According to the preferred embodiment of the present disclosure, thepolymer material includes a polymer compound represented by ChemicalFormula I (hereinafter also referred to as “polymer compound 4”). In amore preferred embodiment, the polymer material is polymer compound 4.

The polymer compound 4 may be represented by Chemical Formula I-2:

In the chemical formula,

A is a monomer unit including at least one triarylamine group,

B′ is a monomer unit having at least three linking points in thecopolymer,

C′ is an aromatic monomer unit or its deuterated analog,

E is the same or different and is independently H, D, a halide, an alkylgroup, a silyl group, a germanyl group, an aryl group, an arylaminogroup, a siloxane group, a cross-linking group, a deuterated alkylgroup, a deuterated silyl group, a deuterated germanyl group, adeuterated aryl group, a deuterated arylamino group, a deuteratedsiloxane group, or a deuterated cross-linking group, and

a, b, and c are mole fractions, the same or different, a+b+c=1, and aand b are not zero.

Chemical Formula I-2 may be represented by Chemical Formula I-2′.

In Chemical Formula I-2′,

a1, b1, c1, and e1 satisfy a1+b1+c1+e1=1 and a1 and b1 are molefractions of reactive monomers which are not zero,

z is an integer of 3 or more,

* represents a linking point in the copolymer, and

A, B′, C′, and E are the same as defined above.

The monomer units A, B′, and C′ are all different.

The monomer units A, B′, and C′ may independently have a substituent D,F, CN, an alkyl group, a fluoroalkyl group, an aryl group, a heteroarylgroup, an amino group, a silyl group, a germanyl group, an alkoxy group,an aryloxy group, a fluoroalkoxy group, a siloxane group, a siloxygroup, a deuterated alkyl group, a deuterated partly fluorinated alkylgroup, a deuterated aryl group, a deuterated heteroaryl group, adeuterated amino group, a deuterated silyl group, a deuterated germanylgroup, a deuterated alkoxy group, a deuterated aryloxy group, adeuterated fluoroalkoxy group, a deuterated siloxane group, a deuteratedsiloxy group, and a cross-linking group, and a combination thereof.

When E is not H, D, or a halide, E may have a substituent D, F, CN, analkyl group, a fluoroalkyl group, an aryl group, a heteroaryl group, anamino group, a silyl group, a germanyl group, an alkoxy group, anaryloxy group, a fluoroalkoxy group, a siloxane group, a siloxy group, adeuterated alkyl group, a deuterated partly fluorinated alkyl group, adeuterated aryl group, a deuterated heteroaryl group, a deuterated aminogroup, a deuterated silyl group, a deuterated germanyl group, adeuterated alkoxy group, a deuterated aryloxy group, a deuteratedfluoroalkoxy group, a deuterated siloxane group, a deuterated siloxygroup, and a cross-linking group, and a combination thereof.

All embodiments of A, B′, C′ and E described in Chemical Formula I-2 areapplied to Chemical Formula I-2′ in the same manner.

In some embodiments of Chemical Formula I-2, A, and optional C arecontrolled as a regular alternate pattern.

In some embodiments of Chemical Formula I-2, A, and optional C arecontrolled as a block of homogeneous monomers.

In some embodiments of Chemical Formula I-2, A, B′, and optional C arerandomly disposed.

The carbon number of the alkyl group is more desirably in the followingtype.

For example, when the ligand of the quantum dot is a long chainalkyl-containing compound such as oleic acid, oleylamine, ortrioctylphosphine, the compound included in the hole transport layer mayalso desirably include a compound having a long chain alkyl group. Thisis because the ligand of the quantum dot and the alkyl group present inthe hole transport layer may interact with each other, thereby improvingeffects such as hole injectability.

In addition, when the solvent that disperses the quantum dot is along-chain hydrocarbon-based solvent, it is desirable that the number ofthe alkyl group in the polymer compound is small in terms of securing aresidual film ratio of the hole transport layer.

Therefore, as the alkyl group, a linear or branched C1 to C18 alkylgroup is more desirable. The alkyl group may be appropriately selectedaccording to the used quantum dot or the solvent that disperses thequantum dot.

The carbon number of the alkoxy group is more desirably in the followingtype.

For example, when the ligand of the quantum dot is a long chainalkyl-containing compound such as oleic acid, oleylamine, ortrioctylphosphine, the compound included in the hole transport layer mayalso desirably include a compound having a long chain alkoxy group. Thisis because the ligand of the quantum dot and the alkoxy group present inthe hole transport layer may interact with each other, thereby improvingeffects such as hole injectability.

In addition, when the solvent that disperses the quantum dot is along-chain hydrocarbon-based solvent, it is desirable that the number ofthe alkoxy group in the polymer compound is small in terms of securing aresidual film ratio of the hole transport layer.

Therefore, as the alkoxy group, a linear or branched C1 to C18 alkoxygroup is more desirable. These alkoxy groups may be appropriatelyselected according to the used quantum dot or the solvent that dispersesthe quantum dot.

In some embodiments, distributions of monomer segments may bemanipulated to optimize properties of the compounds represented byChemical Formula I-2 for use in electronic devices. In some embodiments,different distributions may result in different degrees of discontinuouspacking that ultimately determines the involved film forming properties.

In some embodiments, the copolymer represented by Chemical Formula I-2may be deuterated. The term “deuterated” is intended to mean that atleast one hydrogen (“H”) is replaced by deuterium (“D”). The term“deuterated analog” refers to a structure analog of any compound orgroup in which one or more available hydrogens are replaced bydeuterium. In the deuterated copolymer or the deuterated analog, thedeuterium is at least 100 times the natural presence level. In someembodiments, the copolymer is at least 10% deuterated. “% deuterated”means a ratio of deuteron relative to a sum of proton and deuteron,expressed as a percentage. In some embodiments, the copolymer is atleast 10% deuterated. In some embodiments, the polymer compound 3 may beat least 20% deuterated; in some embodiments, it may be at least 30%deuterated; in some embodiments, it may be at least 40% deuterated; insome embodiments, it may be at least 50% deuterated; in someembodiments, it may be at least 60% deuterated; in some embodiments, itmay be at least 70% deuterated; in some embodiments, it may be at least80% deuterated; in some embodiments, it may be at least 90% deuterated;and in some embodiments, it may be 100% deuterated.

The deuterium may be present in one or more of monomer units A, B′, andC′. The deuterium may be present in the copolymer main chain, pendantgroups, or both.

The monomer unit A is an aromatic monomer unit including at least onetriarylamino group.

The monomer unit A is a bifunctional monomer unit and has only twolinking points in the copolymer.

In some embodiments, the monomer unit A may be represented by ChemicalFormula II.

In the chemical formula,

Ar¹ is the same or different and is independently an aryl group or adeuterated aryl group;

Ar³ is the same or different and is independently an aryl group or adeuterated aryl group;

X is the same or different and is independently a single bond, an arylgroup, and a deuterated aryl group; and

* indicates a linking point in the copolymer.

In some embodiments, the monomer unit A may be represented by ChemicalFormula III.

In the chemical formula,

Ar¹ is the same or different and is independently an aryl group or adeuterated aryl group;

Ar² is the same or different and is independently an aryl group or adeuterated aryl group;

Ar³ is the same or different and is independently an aryl group or adeuterated aryl group;

q is an integer of greater than or equal to 0; and

* indicates a linking point in the copolymer.

In some embodiments, the monomer unit A may be represented by ChemicalFormula III-a.

In the chemical formula, Ar¹, Ar², Ar³, and * are the same as defined inChemical Formula III.

In some embodiments, the monomer unit A may be represented by ChemicalFormula III-b.

In the chemical formula,

Ar² is the same or different and is independently an aryl group or adeuterated aryl group;

R¹ to R⁵ are the same or different and are independently D, F, CN, analkyl group, a fluoroalkyl group, an aryl group, a heteroaryl group, anamino group, a silyl group, a germanyl group, an alkoxy group, anaryloxy group, a fluoroalkoxy group, a siloxane group, a siloxy group, adeuterated alkyl group, a deuterated partly fluorinated alkyl group, adeuterated aryl group, a deuterated heteroaryl group, a deuterated aminogroup, a deuterated silyl group, a deuterated germanyl group, adeuterated alkoxy group, a deuterated aryloxy group, a deuteratedfluoroalkoxy group, a deuterated siloxane group, a deuterated siloxygroup, and a cross-linking group, or adjacent R¹'s or adjacent R⁵'s arelinked to each other to form a condensed 5-membered or 6-membered ring;

k is the same or different and is independently an integer of 0 to 4;

g is an integer of 0 to 3;

h and h1 are the same or different and are independently 1 or 2; and

* indicates a linking point in the copolymer.

The carbon number of the alkyl group is more desirably in the followingtype.

For example, when the ligand of the quantum dot is a long chainalkyl-containing compound such as oleic acid, oleylamine, ortrioctylphosphine, the compound included in the hole transport layer mayalso desirably include a compound having a long chain alkyl group. Thisis because the ligand of the quantum dot and the alkyl group present inthe hole transport layer may interact with each other, thereby improvingeffects such as hole injectability.

In addition, when the solvent that disperses the quantum dot is along-chain hydrocarbon-based solvent, it is desirable that the number ofthe alkyl group in the polymer compound is small in terms of securing aresidual film ratio of the hole transport layer.

Therefore, as the alkyl group, a linear or branched C1 to C18 alkylgroup is more desirable. The alkyl group may be appropriately selectedaccording to the used quantum dot or the solvent that disperses thequantum dot.

The carbon number of the alkoxy group is more desirably in the followingtype.

For example, when the ligand of the quantum dot is a long chainalkyl-containing compound such as oleic acid, oleylamine, ortrioctylphosphine, the compound included in the hole transport layer mayalso desirably include a compound having a long chain alkoxy group. Thisis because the ligand of the quantum dot and the alkoxy group present inthe hole transport layer may interact with each other, thereby improvingeffects such as hole injectability.

In addition, when the solvent that disperses the quantum dot is along-chain hydrocarbon-based solvent, it is desirable that the number ofthe alkoxy group in the polymer compound is small in terms of securing aresidual film ratio of the hole transport layer.

Therefore, as the alkoxy group, a linear or branched C1 to C18 alkoxygroup is more desirable. These alkoxy groups may be appropriatelyselected according to the used quantum dot or the solvent that dispersesthe quantum dot.

In some embodiments, the monomer unit A may be represented by ChemicalFormula IV.

In the chemical formula,

Ar³ is the same or different and is independently an aryl group or adeuterated aryl group;

Ar⁴ is the same or different and is independently phenylene, substitutedphenylene, naphthylene, substituted naphthylene, and a deuterated analogthereof;

T¹ and T² are the same or different and are independently a conjugatedmoiety linked as a non-planar structure or a deuterated analog thereof;

d is the same or different and is independently an integer of 1 to 6,

e is the same or different and is independently an integer of 1 to 6,and

* indicates a linking point in the copolymer.

In some embodiments, the monomer unit A may be represented by ChemicalFormula V-a or Chemical Formula V-b.

In the chemical formula,

Ar³ is an aryl group or a deuterated aryl group;

Ar⁵, Ar⁶, and Ar⁷ are the same or different and are independently anaryl group or a deuterated aryl group;

R¹ and R² are the same or different and are independently D, F, CN, analkyl group, a fluoroalkyl group, an aryl group, a heteroaryl group, anamino group, a silyl group, a germanyl group, an alkoxy group, anaryloxy group, a fluoroalkoxy group, a siloxane group, a siloxy group, adeuterated alkyl group, a deuterated partly fluorinated alkyl group, adeuterated aryl group, a deuterated heteroaryl group, a deuterated aminogroup, a deuterated silyl group, a deuterated germanyl group, adeuterated alkoxy group, a deuterated aryloxy group, a deuteratedfluoroalkoxy group, a deuterated siloxane group, a deuterated siloxygroup, and a cross-linking group, or adjacent groups R¹ and R² arelinked to form a condensed ring;

k1 is an integer of 0 to 4;

g1 is the same or different and is independently an integer of 0 to 3;and

* indicates a linking point in the copolymer.

The carbon number of the alkyl group is more desirably in the followingtype.

For example, when the ligand of the quantum dot is a long chainalkyl-containing compound such as oleic acid, oleylamine, ortrioctylphosphine, the compound included in the hole transport layer mayalso desirably include a compound having a long chain alkyl group. Thisis because the ligand of the quantum dot and the alkyl group present inthe hole transport layer may interact with each other, thereby improvingeffects such as hole injectability.

In addition, when the solvent that disperses the quantum dot is along-chain hydrocarbon-based solvent, it is desirable that the number ofthe alkyl group in the polymer compound is small in terms of securing aresidual film ratio of the hole transport layer.

Therefore, as the alkyl group, a linear or branched C1 to C18 alkylgroup is more desirable. The alkyl group may be appropriately selectedaccording to the used quantum dot or the solvent that disperses thequantum dot.

The carbon number of the alkoxy group is more desirably in the followingtype.

For example, when the ligand of the quantum dot is a long chainalkyl-containing compound such as oleic acid, oleylamine, ortrioctylphosphine, the compound included in the hole transport layer mayalso desirably include a compound having a long chain alkoxy group. Thisis because the ligand of the quantum dot and the alkoxy group present inthe hole transport layer may interact with each other, thereby improvingeffects such as hole injectability.

In addition, when the solvent that disperses the quantum dot is along-chain hydrocarbon-based solvent, it is desirable that the number ofthe alkoxy group in the polymer compound is small in terms of securing aresidual film ratio of the hole transport layer.

Therefore, as the alkoxy group, a linear or branched C1 to C18 alkoxygroup is more desirable. These alkoxy groups may be appropriatelyselected according to the used quantum dot or the solvent that dispersesthe quantum dot.

In some embodiments of the chemical formula, Ar¹ is an aryl group havingat least one condensed ring.

In some embodiments of the chemical formula, Ar¹ may be a naphthylgroup, an anthracenyl group, a naphthylphenyl group, a phenylnaphthylgroup, a fluorenyl group, and a substituted derivative thereof, and adeuterated derivative thereof.

In some embodiments of the chemical formula, Ar¹ may be an aryl groupwithout a condensed ring.

In some embodiments of the chemical formula, Ar¹ may be an aryl group ora substituted aryl group.

In some embodiments of the chemical formula, Ar¹ has at least onesubstituent of D, F, CN, an alkyl group, a fluoroalkyl group, an arylgroup, a heteroaryl group, an amino group, a silyl group, a germanylgroup, an alkoxy group, an aryloxy group, a fluoroalkoxy group, asiloxane group, a siloxy group, a cross-linking group, a deuteratedalkyl group, a deuterated partly fluorinated alkyl group, a deuteratedaryl group, a deuterated heteroaryl group, a deuterated amino group, adeuterated silyl group, a deuterated germanyl group, a deuterated alkoxygroup, a deuterated aryloxy group, a deuterated fluoroalkoxy group, adeuterated siloxane group, a deuterated siloxy group, or deuteratedcross-linking group. In some embodiments, the substituent is D, an alkylgroup, an arylamino group, a hydrocarbon aryl group, a deuterated alkylgroup, a deuterated arylamino group, or a deuterated hydrocarbon arylgroup.

In some embodiments of the chemical formula, Ar¹ is a hydrocarbon arylgroup.

In some embodiments of the chemical formula, Ar¹ is a heteroaryl group.

In some embodiments of the chemical formula, Ar¹ is represented byChemical Formula a.

In the chemical formula,

R⁹ is the same or different and is independently D, an alkyl group, analkoxy group, a silyl group, a germanyl group, and a substitutedderivative thereof, and a deuterated analog thereof or adjacent R⁹'s arelinked to each other to form a condensed ring;

p is the same or different and is independently an integer 0 to 4;

r is an integer of 1 to 5; and

** indicates a linking point.

The carbon number of the alkyl group is more desirably in the followingtype.

For example, when the ligand of the quantum dot is a long chainalkyl-containing compound such as oleic acid, oleylamine, ortrioctylphosphine, the compound included in the hole transport layer mayalso desirably include a compound having a long chain alkyl group. Thisis because the ligand of the quantum dot and the alkyl group present inthe hole transport layer may interact with each other, thereby improvingeffects such as hole injectability.

In addition, when the solvent that disperses the quantum dot is along-chain hydrocarbon-based solvent, it is desirable that the number ofthe alkyl group in the polymer compound is small in terms of securing aresidual film ratio of the hole transport layer.

Therefore, as the alkyl group, a linear or branched C1 to C18 alkylgroup is more desirable. The alkyl group may be appropriately selectedaccording to the used quantum dot or the solvent that disperses thequantum dot.

The carbon number of the alkoxy group is more desirably in the followingtype.

For example, when the ligand of the quantum dot is a long chainalkyl-containing compound such as oleic acid, oleylamine, ortrioctylphosphine, the compound included in the hole transport layer mayalso desirably include a compound having a long chain alkoxy group. Thisis because the ligand of the quantum dot and the alkoxy group present inthe hole transport layer may interact with each other, thereby improvingeffects such as hole injectability.

In addition, when the solvent that disperses the quantum dot is along-chain hydrocarbon-based solvent, it is desirable that the number ofthe alkoxy group in the polymer compound is small in terms of securing aresidual film ratio of the hole transport layer.

Therefore, as the alkoxy group, a linear or branched C1 to C18 alkoxygroup is more desirable. These alkoxy groups may be appropriatelyselected according to the used quantum dot or the solvent that dispersesthe quantum dot.

In some embodiments of the above chemical formula, Ar¹ may berepresented by Chemical Formula b.

In the chemical formula, R⁹, p, r, and ** are the same as those definedin Chemical Formula a.

In some embodiments of the chemical formula, Ar¹ may be represented byChemical Formula c.

In the chemical formula, R⁹, p, r, and ** are the same as those definedin Chemical Formula a.

In some embodiments of the chemical formula, Ar¹ is a phenyl group, abiphenyl group, a terphenyl group, a 1-naphthyl group, a 2-naphthylgroup, an anthracenyl group, a fluorenyl group, and a deuterated analogthereof, and derivatives having at least one substituent being a fluorogroup, an alkyl group, an alkoxy group, a silyl group, a germanyl group,a siloxy group, or a cross-linking group, or a deuterated analogthereof.

The carbon number of the alkyl group is more desirably in the followingtype.

For example, when the ligand of the quantum dot is a long chainalkyl-containing compound such as oleic acid, oleylamine, ortrioctylphosphine, the compound included in the hole transport layer mayalso desirably include a compound having a long chain alkyl group. Thisis because the ligand of the quantum dot and the alkyl group present inthe hole transport layer may interact with each other, thereby improvingeffects such as hole injectability.

In addition, when the solvent that disperses the quantum dot is along-chain hydrocarbon-based solvent, it is desirable that the number ofthe alkyl group in the polymer compound is small in terms of securing aresidual film ratio of the hole transport layer.

Therefore, as the alkyl group, a linear or branched C1 to C18 alkylgroup is more desirable. The alkyl group may be appropriately selectedaccording to the used quantum dot or the solvent that disperses thequantum dot.

The carbon number of the alkoxy group is more desirably in the followingtype.

For example, when the ligand of the quantum dot is a long chainalkyl-containing compound such as oleic acid, oleylamine, ortrioctylphosphine, the compound included in the hole transport layer mayalso desirably include a compound having a long chain alkoxy group. Thisis because the ligand of the quantum dot and the alkoxy group present inthe hole transport layer may interact with each other, thereby improvingeffects such as hole injectability.

In addition, when the solvent that disperses the quantum dot is along-chain hydrocarbon-based solvent, it is desirable that the number ofthe alkoxy group in the polymer compound is small in terms of securing aresidual film ratio of the hole transport layer.

Therefore, as the alkoxy group, a linear or branched C1 to C18 alkoxygroup is more desirable. These alkoxy groups may be appropriatelyselected according to the used quantum dot or the solvent that dispersesthe quantum dot.

All embodiments of Ar¹ are applied to Ar³, Ar⁵, Ar⁶, and Ar⁷ in the samemanner.

In some embodiments of the chemical formula, Are may be an aryl grouphaving at least one condensed ring.

In some embodiments of the chemical formula, Ar² is a naphthyl group, ananthracenyl group, a naphthylphenyl group, a phenylnaphthyl group, afluorenyl group, and a substituted derivative thereof, or a deuteratedderivative thereof.

In some embodiments of the chemical formula, Ar² is an aryl groupwithout condensed ring.

In some embodiments of the chemical formula, Ar² may be an aryl group ora substituted aryl group.

In some embodiments of the chemical formula, Ar² may be a hydrocarbonaryl group.

In some embodiments of the chemical formula, Ar² may be a heteroarylgroup.

In some embodiments of the chemical formula, Ar² may be represented byChemical Formula d.

R⁹ is the same or different and is independently D, an alkyl group, analkoxy group, a silyl group, a germanyl group, and a substitutedderivative thereof, and a deuterated analog thereof or adjacent R⁹'s arelinked to each other to form a condensed ring;

p is the same or different and is independently an integer 0 to 4;

q is an integer of 0 to 5;

r is an integer of 1 to 5; and

** indicates a linking point.

The carbon number of the alkyl group is more desirably in the followingtype.

For example, when the ligand of the quantum dot is a long chainalkyl-containing compound such as oleic acid, oleylamine, ortrioctylphosphine, the compound included in the hole transport layer mayalso desirably include a compound having a long chain alkyl group. Thisis because the ligand of the quantum dot and the alkyl group present inthe hole transport layer may interact with each other, thereby improvingeffects such as hole injectability.

In addition, when the solvent that disperses the quantum dot is along-chain hydrocarbon-based solvent, it is desirable that the number ofthe alkyl group in the polymer compound is small in terms of securing aresidual film ratio of the hole transport layer.

Therefore, as the alkyl group, a linear or branched C1 to C18 alkylgroup is more desirable. The alkyl group may be appropriately selectedaccording to the used quantum dot or the solvent that disperses thequantum dot.

The carbon number of the alkoxy group is more desirably in the followingtype.

For example, when the ligand of the quantum dot is a long chainalkyl-containing compound such as oleic acid, oleylamine, ortrioctylphosphine, the compound included in the hole transport layer mayalso desirably include a compound having a long chain alkoxy group. Thisis because the ligand of the quantum dot and the alkoxy group present inthe hole transport layer may interact with each other, thereby improvingeffects such as hole injectability.

In addition, when the solvent that disperses the quantum dot is along-chain hydrocarbon-based solvent, it is desirable that the number ofthe alkoxy group in the polymer compound is small in terms of securing aresidual film ratio of the hole transport layer.

Therefore, as the alkoxy group, a linear or branched C1 to C18 alkoxygroup is more desirable. These alkoxy groups may be appropriatelyselected according to the used quantum dot or the solvent that dispersesthe quantum dot.

In some embodiments of the chemical formula, Ar² may be represented byChemical Formula e.

In the chemical formula, R⁹, p, r, and ** are the same as those definedin Chemical Formula d.

In some embodiments of the chemical formula, Ar² may be represented byChemical Formula f.

In the chemical formula, R⁹, p, q, r, and ** are the same as thosedefined in Chemical Formula d.

In some embodiments of the chemical formula, Ar² is a phenyl group, abiphenyl group, a terphenyl group, a 1-naphthyl group, a 2-naphthylgroup, an anthracenyl group, a fluorenyl group, or a deuterated analogthereof, and derivatives having at least one substituent being a fluorogroup, an alkyl group, an alkoxy group, a silyl group, a germanyl group,a siloxy group, or a cross-linking group, or a deuterated analogthereof.

The carbon number of the alkyl group is more desirably in the followingtype.

For example, when the ligand of the quantum dot is a long chainalkyl-containing compound such as oleic acid, oleylamine, ortrioctylphosphine, the compound included in the hole transport layer mayalso desirably include a compound having a long chain alkyl group. Thisis because the ligand of the quantum dot and the alkyl group present inthe hole transport layer may interact with each other, thereby improvingeffects such as hole injectability.

In addition, when the solvent that disperses the quantum dot is along-chain hydrocarbon-based solvent, it is desirable that the number ofthe alkyl group in the polymer compound is small in terms of securing aresidual film ratio of the hole transport layer.

Therefore, as the alkyl group, a linear or branched C1 to C18 alkylgroup is more desirable. The alkyl group may be appropriately selectedaccording to the used quantum dot or the solvent that disperses thequantum dot.

The carbon number of the alkoxy group is more desirably in the followingtype.

For example, when the ligand of the quantum dot is a long chainalkyl-containing compound such as oleic acid, oleylamine, ortrioctylphosphine, the compound included in the hole transport layer mayalso desirably include a compound having a long chain alkoxy group. Thisis because the ligand of the quantum dot and the alkoxy group present inthe hole transport layer may interact with each other, thereby improvingeffects such as hole injectability.

In addition, when the solvent that disperses the quantum dot is along-chain hydrocarbon-based solvent, it is desirable that the number ofthe alkoxy group in the polymer compound is small in terms of securing aresidual film ratio of the hole transport layer.

Therefore, as the alkoxy group, a linear or branched C1 to C18 alkoxygroup is more desirable. These alkoxy groups may be appropriatelyselected according to the used quantum dot or the solvent that dispersesthe quantum dot.

In some embodiments of the chemical formulae, g=0.

In some embodiments of the chemical formulae, g=1.

In some embodiments of the chemical formulae, g>0.

In some embodiments of the chemical formulae, g1=0.

In some embodiments of the chemical formulae, g1=1.

In some embodiments of the chemical formulae, g1>0.

In some embodiments of the chemical formulae, k=0.

In some embodiments of the chemical formulae, k=1.

In some embodiments of the chemical formulae, k>0.

In some embodiments of the chemical formulae, k1=0.

In some embodiments of the chemical formulae, k1=1.

In some embodiments of the chemical formulae, k1>0.

In some embodiments of the chemical formulae, p=0.

In some embodiments of the chemical formulae, p=1.

In some embodiments of the chemical formulae, p>0.

In some embodiments of the chemical formulae, q=0.

In some embodiments of the chemical formulae, q=1.

In some embodiments of the chemical formulae, q>0.

In some embodiments of the chemical formulae, r=1.

In some embodiments of the chemical formulae, r=2.

In some embodiments of the chemical formulae, r=3.

In some embodiments of the chemical formulae, R¹ is D or a C1 to C10alkyl group. In some embodiments, the alkyl group may be deuterated.

In some embodiments of the chemical formulae, R¹ is a C1 to C10 silylgroup. In some embodiments, the silyl group may be deuterated.

In some embodiments of the chemical formulae, R¹ is a C6 to C20 arylgroup or a C6 to C20 deuterated aryl group. In some embodiments, arylgroup may be hydrocarbon aryl group. In some embodiments, aryl group maybe a C3 to C20 heteroaryl group.

In some embodiments of the chemical formulae, R¹ is an amino group. Insome embodiments, the amino group may be deuterated.

All embodiments of R¹ are applied to R², R³, R⁴, R⁵, and R⁹ in the samemanner.

Embodiments of the above chemical formulae may be combined with one ormore another embodiment, so long as they are not mutually exclusive. Aperson of an ordinary skill in the art will understand which embodimentsare mutually exclusive. Accordingly, a person of an ordinary skill inthe art may readily determine a combination of embodiments intended bythe present application.

Some non-limiting examples of the monomer unit A are shown below.

The monomer unit B′ is a multi-functional branched monomer unit havingat least three linking points in the copolymer.

In some embodiments, the monomer unit B′ has 3 to 6 linking points.

In some embodiments, the monomer unit B′ has three linking points.

In some embodiments, the monomer unit B′ has four linking points.

In some embodiments, the monomer unit B′ has five linking points.

In some embodiments, the monomer unit B′ has six linking points.

In some embodiments, the monomer unit B′ is aromatic.

In some embodiments, the monomer unit B′ does not have a ringheteroatom.

In some embodiments, the monomer unit B′ is an aromatic group having abranched alkyl group.

In some embodiments, the monomer unit B′ is an aromatic group having abranched aromatic group.

In some embodiments, the monomer unit B′ is a triarylamine group.

In some embodiments, the monomer unit B′ may be represented by ChemicalFormula VI.

In the chemical formula,

Z is a cyclic aliphatic moiety, an aromatic moiety, a deuterated cyclicaliphatic moiety, or a deuterated aromatic moiety which have C, Si, Ge,N, and at least three bonding positions;

Y is a single bond, an alkyl group, an aromatic moiety, a deuteratedalkyl group, or a deuterated aromatic moiety, when Y is a single bond,an alkyl group, or a deuterated alkyl group, Z is an aromatic moiety ora deuterated aromatic moiety;

s is an integer ranging from 3 to the maximum number of availablebonding positions of Z; and

* indicates a linking point in the copolymer.

The carbon number of the alkyl group is more desirably in the followingtype.

For example, when the ligand of the quantum dot is a long chainalkyl-containing compound such as oleic acid, oleylamine, ortrioctylphosphine, the compound included in the hole transport layer mayalso desirably include a compound having a long chain alkyl group. Thisis because the ligand of the quantum dot and the alkyl group present inthe hole transport layer may interact with each other, thereby improvingeffects such as hole injectability.

In addition, when the solvent that disperses the quantum dot is along-chain hydrocarbon-based solvent, it is desirable that the number ofthe alkyl group in the polymer compound is small in terms of securing aresidual film ratio of the hole transport layer.

Therefore, as the alkyl group, a linear or branched C1 to C18 alkylgroup is more desirable. The alkyl group may be appropriately selectedaccording to the used quantum dot or the solvent that disperses thequantum dot.

In some embodiments, the monomer unit B′ may be represented by one ofChemical Formula VII, Chemical Formula VIII, Chemical Formula IX,Chemical Formula X, and Chemical Formula XI.

In the chemical formulae,

Ar⁸ is an aromatic moiety or a deuterated aromatic moiety which have atleast three binding positions;

R⁶ is the same or different and is independently D, F, CN, an alkylgroup, a fluoroalkyl group, an aryl group, a heteroaryl group, an aminogroup, a silyl group, a germanyl group, an alkoxy group, an aryloxygroup, a fluoroalkoxy group, a siloxane group, a siloxy group, adeuterated alkyl group, a deuterated partly fluorinated alkyl group, adeuterated aryl group, a deuterated heteroaryl group, a deuterated aminogroup, a deuterated silyl group, a deuterated germanyl group, adeuterated alkoxy group, a deuterated aryloxy group, a deuteratedfluoroalkoxy group, a deuterated siloxane group, a deuterated siloxygroup, and a cross-linking group, or adjacent R⁶'s are linked to eachother to form a 5-membered or 6-membered condensed ring;

k is the same or different and is independently an integer ranging from0 to 4;

k1 is an integer ranging from 0 to 5; and

* indicates a linking point in the copolymer.

The carbon number of the alkyl group is more desirably in the followingtype.

For example, when the ligand of the quantum dot is a long chainalkyl-containing compound such as oleic acid, oleylamine, ortrioctylphosphine, the compound included in the hole transport layer mayalso desirably include a compound having a long chain alkyl group. Thisis because the ligand of the quantum dot and the alkyl group present inthe hole transport layer may interact with each other, thereby improvingeffects such as hole injectability.

In addition, when the solvent that disperses the quantum dot is along-chain hydrocarbon-based solvent, it is desirable that the number ofthe alkyl group in the polymer compound is small in terms of securing aresidual film ratio of the hole transport layer.

Therefore, as the alkyl group, a linear or branched C1 to C18 alkylgroup is more desirable. The alkyl group may be appropriately selectedaccording to the used quantum dot or the solvent that disperses thequantum dot.

The carbon number of the alkoxy group is more desirably in the followingtype.

For example, when the ligand of the quantum dot is a long chainalkyl-containing compound such as oleic acid, oleylamine, ortrioctylphosphine, the compound included in the hole transport layer mayalso desirably include a compound having a long chain alkoxy group. Thisis because the ligand of the quantum dot and the alkoxy group present inthe hole transport layer may interact with each other, thereby improvingeffects such as hole injectability.

In addition, when the solvent that disperses the quantum dot is along-chain hydrocarbon-based solvent, it is desirable that the number ofthe alkoxy group in the polymer compound is small in terms of securing aresidual film ratio of the hole transport layer.

Therefore, as the alkoxy group, a linear or branched C1 to C18 alkoxygroup is more desirable. These alkoxy groups may be appropriatelyselected according to the used quantum dot or the solvent that dispersesthe quantum dot.

In some embodiments of Chemical Formula VI, Z is an aromatic moiety of acompound of benzene, naphthalene, anthracene, phenanthrene and asubstituted derivative thereof, and a deuterated analog thereof.

Some non-limiting examples of the monomer unit B′ are shown below.

The monomer unit C′ is an any aromatic monomer unit.

The monomer unit C′ is a bifunctional monomer unit having only twolinking points.

In some embodiments, the monomer unit C′ includes a cross-linking groupor a deuterated cross-linking group.

In some embodiments, the monomer unit C′ may be represented by one ofthe following chemical formulae.

In the chemical formulae,

R¹² is the same or different and is independently D, an alkyl group, asilyl group, a germanyl group, an aryl group, a deuterated alkyl group,a deuterated silyl group, a deuterated germanyl group, and a deuteratedaryl group;

R¹³ is the same or different and is independently H, D, an alkyl group,or a deuterated alkyl group;

R¹⁴ is the same or different and is independently an alkyl group, anaryl group, or a deuterated analog thereof;

R¹⁵ is the same or different and is independently an aryl group or adeuterated aryl group;

f is the same or different and is independently an integer ranging from0 to the maximum number available as a substituent,

t is an integer ranging from 0 to 20, and

** indicates a linking point.

The carbon number of the alkyl group is more desirably in the followingtype.

For example, when the ligand of the quantum dot is a long chainalkyl-containing compound such as oleic acid, oleylamine, ortrioctylphosphine, the compound included in the hole transport layer mayalso desirably include a compound having a long chain alkyl group. Thisis because the ligand of the quantum dot and the alkyl group present inthe hole transport layer may interact with each other, thereby improvingeffects such as hole injectability.

In addition, when the solvent that disperses the quantum dot is along-chain hydrocarbon-based solvent, it is desirable that the number ofthe alkyl group in the polymer compound is small in terms of securing aresidual film ratio of the hole transport layer.

Therefore, as the alkyl group, a linear or branched C1 to C18 alkylgroup is more desirable. The alkyl group may be appropriately selectedaccording to the used quantum dot or the solvent that disperses thequantum dot.

The carbon number of the alkoxy group is more desirably in the followingtype.

For example, when the ligand of the quantum dot is a long chainalkyl-containing compound such as oleic acid, oleylamine, ortrioctylphosphine, the compound included in the hole transport layer mayalso desirably include a compound having a long chain alkoxy group. Thisis because the ligand of the quantum dot and the alkoxy group present inthe hole transport layer may interact with each other, thereby improvingeffects such as hole injectability.

In addition, when the solvent that disperses the quantum dot is along-chain hydrocarbon-based solvent, it is desirable that the number ofthe alkoxy group in the polymer compound is small in terms of securing aresidual film ratio of the hole transport layer.

Therefore, as the alkoxy group, a linear or branched C1 to C18 alkoxygroup is more desirable. These alkoxy groups may be appropriatelyselected according to the used quantum dot or the solvent that dispersesthe quantum dot.

In some embodiments, f is 0 to 2.

In some embodiments, t is 1 to 3.

Some non-limiting examples of any monomer unit C′ are shown below.

E is the end capping unit of the copolymer.

E is a mono-functional unit having only one linking point.

In some embodiments of Chemical Formula I-2, E is H or D.

In some embodiments of Chemical Formula I-2, E is a mono-functionalmonomer unit.

In some embodiments of Chemical Formula I-2, E is a cross-linking groupor a deuterated cross-linking group.

In some embodiments of Chemical Formula I-2, E is a hydrocarbon arylgroup or a deuterated hydrocarbon aryl group.

In some embodiments of Chemical Formula I-2, E is an aryl group, anarylamino group, a cross-linking group, or deuterated analogs thereof.

In some embodiments of Chemical Formula I-2, E is a phenyl group, abiphenyl group, a diphenylamino group, and a substituted derivativethereof, or a deuterated analog thereof. In some embodiments, thesubstituent is a C1 to C10 alkyl group, a cross-linking group, or adeuterated analog thereof.

Some of the non-limiting examples of E are shown below.

In the chemical formula, * indicates a linking point in the copolymer.

In some embodiments of Chemical Formula I-2, a≥0.50.

In some embodiments of Chemical Formula I-2, a=0.50 to 0.99.

In some embodiments of Chemical Formula I-2, a=0.60 to 0.90.

In some embodiments of Chemical Formula I-2, a=0.65 to 0.80.

In some embodiments of Chemical Formula I-2, b≥0.05; and in someembodiments, b≥0.10.

In some embodiments of Chemical Formula I-2, b=0.01 to 0.50.

In some embodiments of Chemical Formula I-2, b=0.05 to 0.45.

In some embodiments of Chemical Formula I-2, b=0.10 to 0.40.

In some embodiments of Chemical Formula I-2, b=0.20 to 0.35.

In some embodiments of Chemical Formula I-2, c=0.

In some embodiments of Chemical Formula I-2, c=0 to 0.20.

In some embodiments of Chemical Formula I-2, c=0.01 to 0.20.

In some embodiments of Chemical Formula I-2, c=0.05 to 0.15.

In some embodiments of Chemical Formula I-2, a mole ratio of A+B′relative to E is in the range of about 40:60 to about 98:2, and in someembodiments, about 50:50 to about 90:10; ad in some embodiments, about60:40 to about 80:20.

In some embodiments of Chemical Formula I-2′, a1=0.30 to 0.90.

In some embodiments of Chemical Formula I-2′, a1=0.40 to 0.80.

In some embodiments of Chemical Formula I-2′, a1=0.50 to 0.80.

In some embodiments of Chemical Formula I-2′, b1=0.05-0.40.

In some embodiments of Chemical Formula I-2′, b1=0.10 to 0.30.

In some embodiments of Chemical Formula I-2′, b1=0.10 to 0.20.

In some embodiments of Chemical Formula I-2′, c1=0.

In some embodiments of Chemical Formula I-2′, c1=0 to 0.15.

In some embodiments of Chemical Formula I-2′, c1=0.01 to 0.15.

In some embodiments of Chemical Formula I-2′, c1=0.05 to 0.12.

In some embodiments of Chemical Formula I-2′, e1=0.05 to 0.60.

In some embodiments of Chemical Formula I-2′, e1=0.10 to 0.50.

In some embodiments of Chemical Formula I-2′, e1=0.15 to 0.35.

In the copolymer type 1, c1=0 and the monomer unit C′ does not exist.The end capping unit E is a cross-linking group.

In the copolymer type 2, c1=0 and the monomer unit C′ does not exist.The end capping unit E is an aryl group.

In the copolymer type 3, c1=0 and the monomer unit C′ does not exist.The end capping unit E is a cross-linking group.

In the copolymer type 4, the monomer unit C′ exists and has across-linking group. The end capping unit E is an aryl group.

In the copolymer type 5, c1=0 and the monomer unit C′ does not exist.The end capping unit E is a cross-linking group.

In the copolymer type 6, c1=0 and the monomer unit C′ does not exist.The end capping unit E is a cross-linking group.

In the copolymer type 7, c1=0 and the monomer unit C′ does not exist.The end capping unit E is an aryl group.

In the copolymer type 8, c1=0 and the monomer unit C′ does not exist.The end capping unit E is a cross-linking group.

In the copolymer type 10, c1=0 and the monomer unit C′ does not exist.The end capping unit E is an aryl group.

In the copolymer type 10, the monomer unit C′ exists and has across-linking group. The end capping unit E is a cross-linking group.

In the copolymer type 11, c1=0 and the monomer unit C′ does not exist.The end capping unit E is a cross-linking group.

In the copolymer type 12, c1=0 and the monomer unit C′ does not exist.The end capping unit E is a cross-linking group.

In the copolymer type 13, c1=0 and the monomer unit C′ does not exist.The end capping unit E is an aryl group.

In the copolymer type 14, c1=0 and the monomer unit C′ does not exist.The monomer unit B′ is a 4-functional. The end capping unit E is an arylgroup.

In the copolymer type 15, c1=0 and the monomer unit C′ does not exist.The end capping unit E is a cross-linking group.

In the copolymer type 16, c1=0 and the monomer unit C′ does not exist.The end capping unit E is a cross-linking group.

In the copolymer type 17, c1=0 and the monomer unit C′ does not exist.The end capping unit E is an aryl group.

In the copolymer type 18, c1=0 and the monomer unit C′ does not exist.The end capping unit E is a cross-linking group.

In the copolymer type 19, c1=0 and the monomer unit C′ does not exist.The end capping unit E is an aryl group.

In the copolymer type 20, c1=0 and the monomer unit C′ does not exist.The end capping unit E is a cross-linking group.

In the copolymer type 21, c1=0 and the monomer unit C′ does not exist.The end capping unit E is a cross-linking group.

The copolymer of Chemical Formula I-2 may be produced using a techniquefor producing C—C or C—N bonds or a known polymerization technique.Various such techniques are known, for example, Suzuki, Yamamoto, Stilleand metal-catalyzed CN coupling using metal catalysts, and metalcatalyzed oxidative direct arylation using metal catalysts.

The deuterated compound may be prepared in a similar manner using adeuterated precursor material or may be more generally prepared bytreating a non-deuterated compound with a deuterated solvent such asd6-benzene under the presence of a Lewis acid H/D exchange catalyst,such as aluminum trichloride or ethyl aluminum dichloride, and the like.

The molecular weight control technology of the polymer and copolymer isknown in the field. The molecular weight of the copolymer described inthis disclosure may usually be controlled by a ratio of monomers in thepolymerization reaction. Depending on the embodiment, the molecularweight may be controlled using a quenching reaction.

In some embodiments, the polymer compound 4 has an intrinsic viscosityof less than about 60 milliliters per gram (mug). A lower viscosity isparticularly useful for inkjet printing applications, since a higherconcentration solution may be dispensed. Depending on the embodiment,the copolymers in this disclosure have an intrinsic viscosity of lessthan about 50 mL/g, less than about 40 mL/g, or less than about 30 mL/g.Depending on the embodiment, the copolymers may be greater than or equalto about 20 mL/g and less than or equal to about 60 mL/g, greater thanor equal to about 20 mL/g and less than or equal to about 50 mL/g, orgreater than or equal to about 20 mL/g and less than or equal to about40 mL/g.

Polymer Compound 5

According to a preferred embodiment of the present disclosure, thepolymer material includes a polymer compound 5 having a structural unit(5-A) represented by Chemical Formula (5-1). According to a morepreferred embodiment, the polymer material is the polymer compound 5having a structural unit (5-A) represented by Chemical Formula (5-1).

The polymer compound 5 (silicon-containing arylamine polymer) accordingto the present embodiment has a structural unit (5-A) represented byChemical Formula (5-1):

The polymer compound 5 may include one type of the structural unit(5-A), or may include two or more types of the structural units (5-A).

In this disclosure, the aforementioned structural unit (5-A) representedby Chemical Formula (5-1) is also simply referred to as “structural unit(5-A)” or “structural unit (5-A) according to the present embodiment”.Similarly, in this disclosure, a polymer having the structural unit(5-A) represented by Chemical Formula (5-1) is also simply referred toas “polymer compound 5”, “polymer compound 5 according to the presentembodiment”, “silicon-containing arylamine polymer” or“silicon-containing arylamine polymer according to the presentembodiment”.

In the structural unit (5-A) of Chemical Formula (5-1), a silicon atomcleaves conjugation of the main chain. Thus, in the case of the polymer,it is possible to increase a triplet energy level and achieve highcurrent efficiency. Therefore, by using the polymer compound 5, it ispossible to manufacture an electroluminescence device exhibiting a highluminous efficiency. In the structural unit (5-A), the main chain iscleaved by silicon atoms. For this reason, the polymer compound 5exhibits properties of a low molecular compound similar to the quantumdot and energy level even if it is polymerized. For this reason, byusing the polymer compound 5, a low driving voltage may be achieved.Thus, polymer compound 5 has a high triplet energy level and may achievehigh current efficiency. Therefore, the electroluminescence devicemanufactured using the polymer compound 5 may exhibit high luminousefficiency. In addition, the polymer compound 5 may suppress an increasein a driving voltage. Therefore, the electroluminescence devicemanufactured using the polymer compound 5 may exhibit high luminousefficiency with a low driving voltage. In addition, since the polymercompound 5 has improved film formability and solvent solubility, it ispossible to form a film in a wet (coating) method. Therefore, by usingthe polymer compound 5, a large area of the electroluminescence deviceand high productivity may be obtained. The above mechanism isspeculative, and the present disclosure is independent of the mechanism.

In Chemical Formula (5-1), Ar₁ may independently be a C6 to C25 aromatichydrocarbon group which may be optionally substituted or a C12 to C25heterocyclic aromatic group which may be optionally substituted. Herein,examples of the C6 to C25 aromatic hydrocarbon group may include, forexample, a monovalent group derived from aromatic hydrocarbon such asbenzene (phenyl group), pentane, indene, naphthalene, anthracene,azulene, heptylene, acenaphthene, phenalene, fluorene, anthraquinoline,phenanthrene, biphenyl, terphenyl, tetraphenyl, pentaphenyl, hexaphenyl,pyrene, 9,9-diphenylfluorene, 9,9′-spirobi[fluorene],9,9-dialkylfluorene, and the like, but are not limited thereto. Inaddition, examples of the C12 to C25 heterocyclic aromatic groupinclude, but are not limited to, for example, a monovalent group deriveda heterocyclic aromatic compound such as acridine, phenazine,benzoquinoline, benzisoquinoline, phenanthridine, phenanthroline,anthraquinone, fluorenone, dibenzofuran, dibenzothiophene, carbazole,imidazophenanthridine, benzimidazofuran, tridine, azadibenzofuran,9-phenylcarbazole, azacarbazole, azadibenzothiophene, diazadibenzofuran,diazacarbazole, diazadibenzothiophene, xanthone, dioxanthone, pyridine,quinoline, anthraquinoline, and the like. Of these, at least one Ar₁ isdesirably a monovalent group derived from a compound of benzene,fluorene, biphenyl, p-terphenyl, 9,9-diphenylfluorene,9,9′-spirobi[fluorene], dibenzofuran, dibenzothiophene, or9-phenylcarbazole. More desirably, both Ar₁'s are desirably monovalentgroups derived from compounds of benzene, fluorene, biphenyl,p-terphenyl, 9,9-diphenylfluorene, 9,9′-spirobi[fluorene], dibenzofuran,dibenzothiophene, or 9-phenylcarbazole. In particular, both Ar₁'s aredesirably biphenyl. With such Ar₁, a higher triplet energy level, alower driving voltage, and higher efficiency may be achieved. In thedesirable form described above, Ar₁ may be unsubstituted or any onehydrogen atom of Ar₁ may be replaced by a substituent.

Herein, when any one hydrogen atom of Ar₁ is replaced, the number ofintroduction of the substituent may be for example, desirably 1 to 3,more desirably 1 or 2, and particularly desirably 1, but is notparticularly limited thereto. In the case where Ar₁ has a substituent,the binding position of the substituent is not particularly limited. Thesubstituent is desirably positioned as far as possible from the nitrogenatom of the main chain to which Ar₁ links. By having a substituent insuch a position, it is possible to achieve a higher triplet energylevel, a lower driving voltage, and higher efficiency.

In addition, when any one of the hydrogen atoms of Ar₁ is replaced, thesubstituent is not particularly limited, but may include a halogen atom(fluorine atom, chlorine atom, bromine atom, iodine atom), an alkylgroup, a cycloalkyl group, a hydroxyalkyl group, an alkoxyalkyl group,an alkoxy group, a cycloalkoxy group, an alkenyl group, an alkynylgroup, an amino group, an aryl group, an aryloxy group, an alkylthiogroup, a cycloalkylthio group, an arylthio group, an alkoxycarbonylgroup, an aryloxycarbonyl group, a hydroxyl group (—OH), a carboxylgroup (—COOH), a thiol group (—SH), a cyano group (—CN), and the like.In the above, they are not substituted with the same substituent. Thatis, the alkyl group as the substituent is not substituted by the alkylgroup.

Herein, the alkyl group may be either linear or branched, but desirablyincludes a C1 to C20 linear or branched alkyl group. Specifically, itmay be a methyl group, an ethyl group, an n-propyl group, an isopropylgroup, an n-butyl group, an isobutyl group, a sec-butyl group, atert-butyl group, an n-pentyl group, an isopentyl group, a tert-pentylgroup, a neopentyl group, a 1,2-dimethylpropyl group, an n-hexyl group,an isohexyl group, a 1,3-dimethylbutyl group, a 1-isopropylpropyl group,a 1,2-dimethylbutyl group, an n-heptyl group, a 1,4-dimethylpentylgroup, a 3-ethylpentyl group, a 2-methyl-1-isopropylpropyl group, a1-ethyl-3-methylbutyl group, an n-octyl group, a 2-ethylhexyl group, a3-methyl-1-isopropylbutyl group, a 2-methyl-1-isopropylbutyl group, a1-tert-butyl-2-methylpropyl group, an n-nonyl group, a3,5,5-trimethylhexyl group, an n-decyl group, an isodecyl group, ann-undecyl group, a 1-methyldecyl group, an n-dodecyl group, ann-tridecyl group, an n-tetradecyl group, an n-pentadecyl group, ann-hexadecyl group, an n-heptadecyl group, an n-octadecyl group, and thelike.

The carbon number of the alkyl group is more desirably in the followingtype.

For example, when the ligand of the quantum dot is a long chainalkyl-containing compound such as oleic acid, oleylamine, ortrioctylphosphine, the compound included in the hole transport layer mayalso desirably include a compound having a long chain alkyl group. Thisis because the ligand of the quantum dot and the alkyl group present inthe hole transport layer may interact with each other, thereby improvingeffects such as hole injectability.

In addition, when the solvent that disperses the quantum dot is along-chain hydrocarbon-based solvent, it is desirable that the number ofthe alkyl group in the polymer compound is small in terms of securing aresidual film ratio of the hole transport layer.

Therefore, as the alkyl group, a linear or branched C1 to C18 alkylgroup is more desirable. The alkyl group may be appropriately selectedaccording to the used quantum dot or the solvent that disperses thequantum dot.

Examples of the cycloalkyl group include for example, a cyclopropylgroup, a cyclobutyl group, a cyclopentyl group, and a cyclohexyl group.

As the hydroxyalkyl group, for example, the alkyl group may besubstituted with 1 to 3 (desirably 1 or 2, and particularly desirably 1)hydroxy groups (for example, hydroxymethyl group, hydroxyethyl group).

As the alkoxyalkyl group, for example, the alkyl group may besubstituted with 1 to 3 (desirably 1 or 2 and particularly desirably 1)alkoxy groups.

The alkoxy group may be, for example, a methoxy group, an ethoxy group,a propoxy group, an isopropoxy group, a butoxy group, a pentyloxy group,a hexyloxy group, a heptyloxy group, an octyloxy group, a nonyloxygroup, a decyloxy group, an undecyloxy group, a dodecyloxy group, atridecyloxy group, a tetradecyloxy group, a pentadecyloxy group, ahexadecyloxy group, a heptadecyloxy group, an octadecyloxy group, a2-ethylhexyloxy group, a 3-ethylpentyloxy group, and the like.

The carbon number of the alkoxy group is more desirably in the followingtype.

For example, when the ligand of the quantum dot is a long chainalkyl-containing compound such as oleic acid, oleylamine, ortrioctylphosphine, the compound included in the hole transport layer mayalso desirably include a compound having a long chain alkoxy group. Thisis because the ligand of the quantum dot and the alkoxy group present inthe hole transport layer may interact with each other, thereby improvingeffects such as hole injectability.

In addition, when the solvent that disperses the quantum dot is along-chain hydrocarbon-based solvent, it is desirable that the number ofthe alkoxy group in the polymer compound is small in terms of securing aresidual film ratio of the hole transport layer.

Therefore, as the alkoxy group, a linear or branched C1 to C18 alkoxygroup is more desirable. These alkoxy groups may be appropriatelyselected according to the used quantum dot or the solvent that dispersesthe quantum dot.

The cycloalkoxy group may include, for example, a cyclopropoxy group, acyclobutoxy group, a cyclopentyloxy group, a cyclohexyloxy group, andthe like.

The alkenyl group may include, for example, a vinyl group, an allylgroup, a 1-propenyl group, an isopropenyl group, a 1-butenyl group, a2-butenyl group, a 3-butenyl group, a 1-pentenyl group, a 2-pentenylgroup, a 3-pentenyl group, a 1-hexenyl group, a 2-hexenyl group, a3-hexenyl group, a 1-heptenyl group, a 2-heptenyl group, a 5-heptenylgroup, a 1-octenyl group, a 3-octenyl group, a 5-octenyl group, and thelike.

The alkynyl group may include, for example, an acetylenyl group, a1-propynyl group, a 2-propynyl group, a 1-butynyl group, a 2-butynylgroup, a 3-butynyl group, a 1-pentynyl group, a 2-pentynyl group, a3-pentynyl group, 1-hexynyl group, a 2-hexynyl group, a 3-hexynyl group,a 1-heptynyl group, a 2-heptynyl group, a 5-heptynyl group, a 1-octynylgroup, a 3-octynyl group, a 5-octynyl group, and the like.

The aryl group may include, for example, a phenyl group, a naphthylgroup, a biphenyl group, a fluorenyl group, an anthryl group, a pyrenylgroup, an azulenyl group, an acenaphthylenyl group, a terphenyl group,or a phenanthryl group.

The aryloxy group may include, for example, a phenoxy group, or anaphthyloxy group.

The alkylthio group may include, for example, a methylthio group, anethylthio group, a propylthio group, a pentylthio group, a hexylthiogroup, an octylthio group, a dodecylthio group, and the like.

The cycloalkylthio group may include, for example, a cyclopentylthiogroup or a cyclohexylthio group.

The arylthio group may include, for example, a phenylthio group, anaphthylthio group, and the like.

The alkoxycarbonyl group may include, for example, a methyloxy carbonylgroup, an ethyloxy carbonyl group, a butyloxy carbonyl group, anoctyloxy carbonyl group, a dodecyloxycarbonyl group, and the like.

The aryloxycarbonyl group may include, for example, a phenyloxycarbonylgroup, a naphthyloxycarbonyl group, and the like.

That is, in the desirable form of the present embodiment, Ar₁ isindependently a group of the following groups. In the followingstructures, R₁₁₁ to R₁₃₃ are independently a hydrogen atom, a C1 to C12linear or branched alkyl group, or a C6 to C25 aromatic hydrocarbongroup which may be optionally substituted. Herein, the C1 to C12 linearor branched alkyl group may be, for example, a methyl group, an ethylgroup, an n-propyl group, an isopropyl group, an n-butyl group, anisobutyl group, a sec-butyl group, a tert-butyl group, an n-pentylgroup, an isopentyl group, a tert-pentyl group, a neopentyl group, a1,2-dimethylpropyl group, an n-hexyl group, an isohexyl group, a1,3-dimethylbutyl group, a 1-isopropylpropyl group, a 1,2-dimethylbutylgroup, an n-heptyl group, a 1,4-dimethylpentyl group, a 3-ethylpentylgroup, a 2-methyl-1-isopropylpropyl group, a 1-ethyl-3-methylbutylgroup, an n-octyl group, a 2-ethylhexyl group, a3-methyl-1-isopropylbutyl group, a 2-methyl-1-isopropylbutyl group, a1-tert-butyl-2-methylpropyl group, an n-nonyl group, a3,5,5-trimethylhexyl group, an n-decyl group, an isodecyl group, ann-undecyl group, a 1-methyldecyl group, an n-dodecyl group, and thelike. In addition, the C6 to C25 aromatic hydrocarbon group may include,for example, the same examples as defined in Ar₁, but is notparticularly limited thereto. In terms of higher triplet energy levelsand lower driving voltages, R₁₁₁ to R₁₃₃ are desirably a hydrogen atomor a linear or branched C2 to C10 alkyl group. More desirably, R₁₁₁ toR₁₃₃ are hydrogen or a C3 to C6 linear alkyl group.

In Chemical Formula (5-1), Ar₂ indicates a C6 to C25 divalent aromatichydrocarbon group which may be optionally substituted or a C12 to C25divalent heterocyclic aromatic group which may be optionallysubstituted. Herein, the C6 to C25 divalent aromatic hydrocarbon groupmay include, for example, a divalent group derived from C6 to C25aromatic hydrocarbon defined in Ar₁, but is not particularly limitedthereto. Similarly, the C12 to C25 divalent heterocyclic aromatic groupmay include, for example, a divalent group derived from the C12 to C25heterocyclic aromatic compound defined in Ar₁, but is not particularlylimited thereto. Of these, Ar₂ is desirably a divalent group derivedfrom benzene, biphenyl, terphenyl, tetraphenyl, pentaphenyl, hexaphenyl,fluorene, 9-phenylcarbazole, dibenzofuran, dibenzothiophene,9,9-diphenylfluorene, and 9,9′-spirobi[fluorene]. More desirably, Ar₂ isdesirably a divalent group derived from phenyl, biphenyl, terphenyl,tetraphenyl, pentaphenyl, or fluorene. In particular, Ar₂ is desirably adivalent group derived from biphenyl, p-terphenyl, p-tetraphenyl, orp-pentaphenyl. Ar₂ is desirably a divalent group derived fromp-pentaphenyl. Such Ar₂ may achieve a higher triplet energy level, alower driving voltage, and higher efficiency. In the desirable formdescribed above, Ar₂ may be unsubstituted or any one hydrogen atom ofAr₂ may be replaced by a substituent.

Herein, when any one or more hydrogen atom of Ar₂ is replaced, thenumber of the substituent is not particularly limited, but may be forexample, desirably 1 to 3, more desirably 1 or 2, and particularlydesirably 1. In the case where Ar₂ has a substituent, the bindingposition of the substituent is not particularly limited. For example, inthe case of a plurality of substituents, the substituents are desirablyin the same aromatic ring or heterocycle, more desirably in the samearomatic ring, and particularly desirably in the same phenyl ring. Forexample, when two substituents are present in the p-phenylene group, thetwo substituents may be present at any of positions 2 and 3, positions 2and 5, and positions 3 and 5, but desirably at positions 2 and 5, andpositions 3 and 5, and particularly desirably at positions 3 and 5. Inthe case where a plurality of substituents are present in a plurality ofaromatic rings or heterocycles linked to each other, the substituentsdesirably exist in an aromatic ring or heterocycle near the center. Byhaving the substituent in such a position, it is possible to achieve ahigher triplet energy level, a lower driving voltage, and higherefficiency.

In addition, when any one of the hydrogen atoms of Ar₂ is replaced, thesubstituent is not particularly limited, but may include the sameexamples as Ar₁.

That is, in the desirable form of the present disclosure, Ar₂ is adivalent group of the following groups. In the following structures,R₂₁₁ to R₂₆₉ are independently a hydrogen atom, a C1 to C12 linear orbranched alkyl group, or a C6 to C25 aromatic hydrocarbon group whichmay be optionally substituted. Herein, the C1 to C12 linear or branchedalkyl group, or the C6 to C25 aromatic hydrocarbon group which may beoptionally substituted is not particularly limited, but may include thesame example as R₁₁₁ to R₁₃₃. In terms of higher triplet energy levelsand lower driving voltages, R₂₁₁ to R₂₆₉ are desirably a hydrogen atomor a linear or branched C2 to C10 alkyl group. More desirably, R₂₁₁ toR₂₆₉ are hydrogen or a C3 to C6 linear alkyl group.

In addition, in Chemical Formula (5-1), R₁ is independently a hydrogenatom, a C1 to C12 linear, branched, or cyclic hydrocarbon group, or a C6to C25 divalent aromatic hydrocarbon group which may be optionallysubstituted. Herein, the C1 to C12 linear, branched, or cyclichydrocarbon group may include, for example, linear or branched alkylgroup, alkenyl group, alkynyl group, and cycloalkyl group, but is notparticularly limited thereto. When R₁ is an alkenyl group or an alkynylgroup, the carbon number of R₁ is greater than or equal to 2 and lessthan or equal to 12. Similarly, when R₁ is a cycloalkyl group, thecarbon number of R₁ is greater than or equal to about 3 and less than orequal to about 12.

The C1 to C12 alkyl group may include, for example, a methyl group, anethyl group, an n-propyl group, an isopropyl group, an n-butyl group, anisobutyl group, a sec-butyl group, a tert-butyl group, an n-pentylgroup, an isopentyl group, a tert-pentyl group, a neopentyl group, a1,2-dimethylpropyl group, an n-hexyl group, an isohexyl group, a1,3-dimethylbutyl group, a 1-isopropylpropyl group, a 1,2-dimethylbutylgroup, an n-heptyl group, a 1,4-dimethylpentyl group, a 3-ethylpentylgroup, a 2-methyl-1-isopropylpropyl group, a 1-ethyl-3-methylbutylgroup, an n-octyl group, a 2-ethylhexyl group, a3-methyl-1-isopropylbutyl group, a 2-methyl-1-isopropylbutyl group, a1-tert-butyl-2-methylpropyl group, an n-nonyl group, a3,5,5-trimethylhexyl group, an n-decyl group, an isodecyl group, ann-undecyl group, a 1-methyldecyl group, an n-dodecyl group, and thelike.

The C2 to C12 alkenyl group may include a vinyl group, an allyl group, a1-propenyl group, a 2-butenyl group, a 1,3-butenthienyl group, a2-pentenyl group, an isopropenyl group, and the like.

The C2 to C12 alkynyl group may include, for example, an ethynyl group,or a propargyl group.

The C3 to C12 cycloalkyl group may include, for example, a cyclopropylgroup, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, andthe like.

Of these, R₁ is independently a hydrogen atom or a C1 to C12 linear orbranched alkyl group. In terms of a higher triplet energy level and alower driving voltage, R₁ is more desirably a hydrogen atom or a C3 toC6 linear alkyl group.

In addition, a polymerization degree of the structural unit (5-A) maybe, for example, an integer from 10 to 1,000, but is not particularlylimited thereto. In terms of a higher triplet energy level and a lowerdriving voltage, the polymerization degree of the structural unit (5-A)is desirably greater than or equal to about 5 and less than or equal toabout 500, more desirably greater than or equal to about 10 and lessthan or equal to about 300, and particularly desirably greater than orequal to about 10 and less than or equal to about 150.

In the present embodiment, in terms of further improvement of thetriplet energy level and hole transport capability, and furtherdecreasing a driving voltage, the structural unit (5-A) represented byChemical Formula (5-1) is desirably the structural units represented byChemical formula (5-A-1) to Chemical formula (5-A-4). Desirably, thestructural unit (5-A) is a structural unit represented by ChemicalFormula (5-A-1). In the following description, “Alkyl” means“unsubstituted or substituted with an alkyl group”. Desirably, “Alkyl”means unsubstitution (i.e., Alkyl=hydrogen atom) or substitution with alinear or branched C1 to C18 alkyl group. More desirably, “Alkyl” meansunsubstitution or substitution with a linear or branched C3 to C6 alkylgroup. In addition, “Alkyl” may be the same alkyl group or a differentalkyl group.

A composition of the structural unit (5-A) in the polymer compound 5 ofthe present embodiment is not particularly limited. Considering theeffect of further improving the hole transport capability of the layer(for example, hole injection layer, hole transport layer) formed usingthe obtained polymer compound 5, the structural unit (5-A) may bedesirably included in an amount of greater than equal to about 10 mol %and less than or equal to about 100 mol %, more desirably greater thanequal to about 50 mol % and less than or equal to about 100 mol %, andparticularly desirably about 100 mol % based on a total structural unitconstituting the polymer compound 5. That is, in the desirable form ofthe present embodiment, the structural unit (5-A) is included in a ratioof greater than or equal to about 10 mol % and less than or equal toabout 100 mol % based on a total structural unit. In the more desirableform of the present embodiment, the structural unit (5-A) is included ina ratio of greater than or equal to about 50 mol % and less than orequal to about 100 mol % based on a total structural unit. In theparticularly desirable form of the present embodiment, the polymercompound 5 consists of structural units (5-A) alone. When the polymercompound 5 includes two or more structural units (5-A), a content of thestructural unit (5-A) means the total amount of the structural units(5-A).

As described above, the polymer compound 5 of the present embodiment maybe composed of the structural unit (5-A) alone. Alternatively, thepolymer compound 5 of the present embodiment may further include astructural unit other than the structural unit (5-A). In the case ofincluding other structural units, other structural units are notparticularly limited as long as they do not inhibit effects of thepolymer compound 5 (particularly high triplet energy level, low drivingvoltage, etc.). Specifically, the structural unit represented byChemical Formula (5-2) may be exemplified. The structural unitrepresented by Chemical Formula (5-2) is also referred to as “structuralunit (5-B)”.

The composition of the structural unit (5-B) in the polymer compound 5of the present embodiment is not particularly limited. Considering theease of film formation by the obtained polymer compound and the furtherimprovement effect of the film strength, the structural unit (5-B) isdesirably included in an amount of greater than or equal to about 1 mol% and less than or equal to about 10 mol % based on a total structuralunit constituting the polymer compound 5. When the polymer compound 5includes two or more structural units (5-B), a content of the structuralunit (5-B) means the total amount of the structural units (5-B).

When the polymer compound 5 is composed of two or more structural units,the structure of the polymer compound 5 is not particularly limited. Thepolymer compound 5 may be any of a random copolymer, an alternatecopolymer, a periodic copolymer, and a block copolymer.

The main chain terminal end of the polymer compound 5 of the presentembodiment is not particularly limited, but is usually hydrogendepending on the type of the used raw material.

The polymer compound 5 of the present embodiment may be synthesized byusing a known organic synthesis method. The specific synthesis method ofthe polymer compound 5 of the present embodiment may be easilyunderstood by a person of an ordinary skill in the art referring to thefollowing examples. Specifically, the polymer compound 5 of the presentembodiment may be prepared by a polymerization reaction using at leastone monomer 5-1 represented by Chemical Formula (5-1), or by acopolymerization reaction at least one monomer 5-1 represented byChemical Formula (5-1) and the other structural units. The monomers usedfor the polymerization of the polymer compound 5 may be synthesized byappropriately combining a known synthesis reaction, and their structuresmay be confirmed by known methods (for example, NMR, LC-MS, etc.).

In Chemical Formula (5-1), Ar₁, Ar₂, and R₁ are the same as defined inChemical Formula (5-1). In addition, X₁ and X₂ are independently ahalogen atom (a fluorine atom, a chlorine atom, a bromine atom, aniodine atom, particularly a bromine atom) or a group having thefollowing structure. In the following structure, R_(A) to R_(D) areindependently a C1 to C3 alkyl group. Desirably, R_(A) to R_(D) may be amethyl group.

According to a preferred embodiment of the present disclosure, thepolymer material includes a polymer compound (hereinafter referred tosimply as “polymer compound 6”) having at least one of a structural unit(6-1) represented by Chemical Formula (6-1) and a structural unit (6-2)represented by Chemical Formula (6-2). According to a more preferredembodiment, the polymer material may be a polymer compound 6.

The polymer compound 6 may be a homopolymer(poly(9,9-dioctylfluorene-co-N-(4-butylphenyl)-diphenylamine, TFB))having the structural unit (6-1) alone. It may also be a homopolymerhaving the structural unit (6-2) alone. Furthermore, a copolymer whichhas the structural unit (6-1) and structural unit (6-2) may be used.

Low Molecular Material

The hole transport layer according to the present disclosure includes alow molecular material along with the polymer material. The lowmolecular material is present in the hole transport layer to fill theso-called gap of the polymer material, and the low molecular compound isnot mixed in the light emitting layer. As a result, a compact holetransport layer may be formed, and the hole transport capability of thehole transport layer is improved. The quantum dot EL device having sucha hole transport layer has improved luminous efficiency and lightemitting life-span.

The low molecular material desirably is a hole transporting material ora wide gap material. In addition, the low molecular material maydesirably be included among one or more types of polymer materials.

A molecular weight of the low molecular material may desirably begreater than or equal to about 100 g/mole and less than or equal toabout 1,500 g/mole. Within such a range, the film may be solidified andsublimation purification may be easily performed, so that a high purityproduct may be easily obtained. In addition, since appropriate molecularsizes may be obtained, filling effect between the gaps of the polymermay be more improved. The molecular weight of the low molecular materialis desirably greater than or equal to about 500 g/mole and less than orequal to about 1,500 g/mole, and desirably greater than or equal toabout 600 g/mole and less than or equal to about 1,300 g/mole.

The molecular weight of the low molecular material is a sum of the atomweight of each atom.

The low molecular material of the present embodiment may be synthesizedby using a known organic synthesis method. The specific synthesis methodof the low molecular material of the present embodiment may be easilyunderstood by a person of an ordinary skill in the art. The structure ofthe low molecular material may be confirmed by a known method (forexample, NMR, LC-MS, etc.).

The low molecular material of the present embodiment may desirablyinclude at least one of the hole transporting material and the wide gapmaterial. By adding the low molecular material, a film density may beincreased to improve hole transport capability and optimize carrierbalance. When the low molecular material is a hole transporting materialand a wide gap material, the low molecular material is not easilydegraded when the device is driven, which is more desirable.

Hereinafter, low molecular compounds 1 to 6, which are a desirableembodiment of the low molecular material, are described. The lowmolecular material may be used alone or in combination of 2 or moretypes.

Low Molecular Compounds 1 and 2

According to the preferred embodiment of the present disclosure, the lowmolecular material may include at least one of a low molecular compoundrepresented by Chemical Formula (L1) (hereinafter also referred to as“low molecular compound 1”) and a low molecular compound represented byChemical Formula (L2) (hereinafter, also referred to as “low molecularcompound 2”). The low molecular compounds 1 and 2 are hole transportingmaterials and when used in combination with the polymer material, thelow molecular compounds 1 and 2 exist to enter the gap of the polymermaterial. Therefore, a more dense hole transport layer may be providedand the hole transport capability of the hole transport layer may beimproved. In addition, since the hole transport capability of the lowmolecular compounds 1 and 2 themselves, which are the hole transportingmaterials to be added, is imparted to the hole transport layer, aneffect of further improving hole transport properties may be obtained.

According to a more desirable embodiment, the low molecular material isat least one type of the low molecular compound 1 and the low molecularcompound 2.

Hereinafter, the low molecular compound 1 and the low molecular compound2 are described.

Low Molecular Compound 1

The low molecular compound 1 is a compound represented by ChemicalFormula (L1).

In Chemical Formula (L1), R is independently a hydrogen atom, adeuterium atom, or a monovalent organic group. In Chemical Formula (L1),a plurality of R's, preferably adjacent R's, may be linked to each otherto form a ring. In view of further improving the effect of the presentdisclosure, in Chemical Formula (L1), R may desirably be a hydrogenatom.

Specific examples of the monovalent organic group may include an alkylgroup, a cycloalkyl group, an alkenyl group, an alkynyl group, an arylgroup, a heteroaryl group, an acyl group, an alkoxycarbonyl group, anamino group, an alkoxy group, a cycloalkyloxy group, an aryloxy group,an aryloxycarbonyl group, an acyloxy group, an acylamino group, analkoxycarbonylamino group, an aryloxycarbonylamino group, asulfonylamino group, a sulfamoyl group, a carbamoyl group, an alkylthiogroup, an arylthio group, a silyl group, a sulfonyl group, a sulfinylgroup, an ureide group, a phosphoric acid amide group, a halogen atom, ahydroxyl group, a mercapto group, a cyano group, a sulfo group, acarboxyl group, a nitro group, a hydroxamic acid group, a sulfino group,a hydrazino group, or an imino group.

The carbon number of the alkyl group is more desirably in the followingtype.

For example, when the ligand of the quantum dot is a long chainalkyl-containing compound such as oleic acid, oleylamine, ortrioctylphosphine, the compound included in the hole transport layer mayalso desirably include a compound having a long chain alkyl group. Thisis because the ligand of the quantum dot and the alkyl group present inthe hole transport layer may interact with each other, thereby improvingeffects such as hole injectability.

In addition, when the solvent that disperses the quantum dot is along-chain hydrocarbon-based solvent, it is desirable that the number ofthe alkyl group in the polymer compound is small in terms of securing aresidual film ratio of the hole transport layer.

Therefore, as the alkyl group, a linear or branched C1 to C18 alkylgroup is more desirable. The alkyl group may be appropriately selectedaccording to the used quantum dot or the solvent that disperses thequantum dot.

The carbon number of the alkoxy group is more desirably in the followingtype.

For example, when the ligand of the quantum dot is a long chainalkyl-containing compound such as oleic acid, oleylamine, ortrioctylphosphine, the compound included in the hole transport layer mayalso desirably include a compound having a long chain alkoxy group. Thisis because the ligand of the quantum dot and the alkoxy group present inthe hole transport layer may interact with each other, thereby improvingeffects such as hole injectability.

In addition, when the solvent that disperses the quantum dot is along-chain hydrocarbon-based solvent, it is desirable that the number ofthe alkoxy group in the polymer compound is small in terms of securing aresidual film ratio of the hole transport layer.

Therefore, as the alkoxy group, a linear or branched C1 to C18 alkoxygroup is more desirable. These alkoxy groups may be appropriatelyselected according to the used quantum dot or the solvent that dispersesthe quantum dot.

In Chemical Formula L1, Ar_(a) may be a group represented by ChemicalFormula (L1-a). In Chemical Formula L1, a plurality of Ar_(a)'s may bethe same or different, but are desirably different. In Chemical FormulaL1, a plurality of Ar_(a)'s, preferably adjacent Ar_(a)'s may be linkedto each other to form a ring.

In Chemical Formula (L1-a), R is independently a hydrogen atom, adeuterium atom, or a monovalent organic group. In Chemical Formula(L1-a), a plurality of R's, preferably adjacent R's, may be linked toeach other to form a ring. Herein, the monovalent organic group mayinclude, for example, a linear or branched C1 to C24 alkyl group, but isnot particularly limited thereto. In addition, in Chemical Formula(L1-a), n is an integer of 0 to 3, desirably 0 to 2, and more desirably0 or 1. In addition, in Chemical Formula (L1-a), * represents a linkingportion with an adjacent atom.

Specific examples of the linear or branched C1 to C24 alkyl group may bea methyl group, an ethyl group, an n-propyl group, an isopropyl group,an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butylgroup, an n-pentyl group, an isopentyl group, a tert-pentyl group, aneopentyl group, a 1,2-dimethylpropyl group, an n-hexyl group, anisohexyl group, a 1,3-dimethylbutyl group, a 1-isopropylpropyl group, a1,2-dimethylbutyl group, an n-heptyl group, a 1,4-dimethylpentyl group,a 3-ethylpentyl group, a 2-methyl-1-isopropylpropyl group, a1-ethyl-3-methylbutyl group, an n-octyl group, a 2-ethylhexyl group, a3-methyl-1-isopropylbutyl group, a 2-methyl-1-isopropylbutyl group, a1-tert-butyl-2-methylpropyl group, an n-nonyl group, a3,5,5-trimethylhexyl group, an n-decyl group, an isodecyl group, ann-undecyl group, a 1-methyldecyl group, an n-dodecyl group, ann-tridecyl group, an n-tetradecyl group, an n-pentadecyl group, ann-hexadecyl group, an n-heptadecyl group, an n-octadecyl group, ann-nonadecyl group, an n-eicosyloxy group, an n-heneicosyl group, ann-docosyl group, an n-tricosyl group, and an n-tetracosyl group.

The carbon number of the alkyl group is more desirably in the followingtype.

For example, when the ligand of the quantum dot is a long chainalkyl-containing compound such as oleic acid, oleylamine, ortrioctylphosphine, the compound included in the hole transport layer mayalso desirably include a compound having a long chain alkyl group. Thisis because the ligand of the quantum dot and the alkyl group present inthe hole transport layer may interact with each other, thereby improvingeffects such as hole injectability.

In addition, when the solvent that disperses the quantum dot is along-chain hydrocarbon-based solvent, it is desirable that the number ofthe alkyl group in the polymer compound is small in terms of securing aresidual film ratio of the hole transport layer.

Therefore, as the alkyl group, a linear or branched C1 to C18 alkylgroup is more desirable. The alkyl group may be appropriately selectedaccording to the used quantum dot or the solvent that disperses thequantum dot.

From the viewpoint of further improving the effect of the presentdisclosure, Ar_(a) may be desirably a group represented by Group L1-A.In Group L1-A, R′ may be a C1 to C24 linear or branched alkyl group anddesirably a C1 to C16 linear alkyl group. In Group L1-A, * represents alinking portion with an adjacent atom.

From the viewpoint of further improving the effect of the presentdisclosure, Ar_(a) may be desirably a group of Group L1-A. In GroupL1-A, dodecyl indicates an n-dodecyl group. In addition, * represents alinking portion with an adjacent atom.

In Chemical Formula L1, Ar_(b) is a group represented by ChemicalFormula (L1-b).

In Chemical Formula (L1-b), R is independently a hydrogen atom, adeuterium atom, or a monovalent organic group. In Chemical Formula(L1-b), a plurality of R's, preferably adjacent R's, may be linked toeach other to form a ring. From the viewpoint of further improving theeffect of the present disclosure, in Chemical Formula (L1-b), R isdesirably a hydrogen atom.

In Chemical Formula (L1-b), m is an integer of 0 to 2, desirably 1 or 2,and more desirably 1. In Chemical Formula (L1-b), * represents a linkingportion with an adjacent atom.

In Chemical Formula L1, Ar_(b) is desirably a group of Group L1-B. InGroup L1-B, R′ is independently a C1 to C24 linear or branched alkylgroup. In Group L1-B, a plurality of R′, preferably adjacent R′ may belinked to each other to form a ring. In Group L1-B, * represents alinking portion with an adjacent atom. Among them, from the viewpoint offurther improving the effect of the present disclosure, Ar_(b) may bedesirably a para-phenylene group.

The carbon number of the alkyl group is more desirably in the followingtype.

For example, when the ligand of the quantum dot is a long chainalkyl-containing compound such as oleic acid, oleylamine, ortrioctylphosphine, the compound included in the hole transport layer mayalso desirably include a compound having a long chain alkyl group. Thisis because the ligand of the quantum dot and the alkyl group present inthe hole transport layer may interact with each other, thereby improvingeffects such as hole injectability.

In addition, when the solvent that disperses the quantum dot is along-chain hydrocarbon-based solvent, it is desirable that the number ofthe alkyl group in the polymer compound is small in terms of securing aresidual film ratio of the hole transport layer.

The alkyl group may be more desirably a linear or branched C1 to C18alkyl group. The alkyl group may be appropriately selected according tothe used quantum dot or the solvent that disperses the quantum dot.

The low molecular compound 1 may be desirably a compound represented byany one of Chemical Formula (L1-1) to Chemical Formula (L1-3).

In Chemical Formula (L1-1) to Chemical Formula (L1-3), the definitionsof R, Ar_(a), and Ar_(b) are the same as those in Chemical Formula (L1).

Specific examples of the low molecular compound 1 may be a compoundrepresented by the following chemical formulae. The low molecularcompound 1 may be used alone or in a combination of two or more types.

The low molecular compound 1 may be synthesized by using a known organicsynthesis method.

Low Molecular Compound 2

Low molecular compound 2 is a compound represented by Chemical Formula(L2).

In Chemical Formula (L2), Ar_(a) is a group represented by ChemicalFormula (L2-a).

In Chemical Formula (L2-a), R is independently a hydrogen atom, adeuterium atom, or a monovalent organic group. In Chemical Formula(L2-a), a plurality of R's, preferably adjacent R's, may be linked toeach other to form a ring. In Chemical Formula (L2-a), Z may be a C1 toC12 linear or branched alkyl group, and desirably C4 to C12 linear alkylgroup. In Chemical Formula (L2-a), * represents a linking portion withan adjacent atom.

From the viewpoint of further improving the effect of the presentdisclosure, in Chemical Formula (L2), Ar_(a) may be desirably a grouprepresented by Chemical Formula (L2-a).

In Chemical Formula (L2-a′), Z is the same define as in Chemical Formula(L2-a). In Chemical Formula (L2-a′), R′ is hydrogen or a methyl group.In Chemical Formula (L2-a′), * represents a linking portion with anadjacent atom.

From the viewpoint of further improving the effect of the presentdisclosure, Ar_(a) may be desirably a group of Group L2-A. In GroupL2-A, * represents a linking portion with an adjacent atom.

In Chemical Formula (L2), X is a group represented by Chemical Formula(L2-b). In Chemical Formula (L2), a plurality of X's may be the same ordifferent. In Chemical Formula (L2), a plurality of X's, preferablyadjacent X's, may be linked to each other to form a ring.

In Chemical Formula (L2-b), R is independently a hydrogen atom, adeuterium atom, or a monovalent organic group. In Chemical Formula(L2-b), a plurality of R's, preferably adjacent R's, may be linked toeach other to form a ring. In addition, in Chemical Formula (L2-b), n isan integer of 0 to 3, desirably 0 to 2, and more desirably 0 or 1. Inaddition, in Chemical Formula (L2-b), * represents a linking portionwith an adjacent atom.

From the viewpoint of further improving the effect of the presentdisclosure, X may be desirably a group of Group L2-B. In Group L2-B, R′may independently be a C1 to C24 linear or branched alkyl group. InGroup L2-B, a plurality of R′, preferably adjacent R′, may be linked toeach other to form a ring. In Group L2-B, * represents a linking portionwith an adjacent atom.

The carbon number of the alkyl group is more desirably in the followingtype.

For example, when the ligand of the quantum dot is a long chainalkyl-containing compound such as oleic acid, oleylamine, ortrioctylphosphine, the compound included in the hole transport layer mayalso desirably include a compound having a long chain alkyl group. Thisis because the ligand of the quantum dot and the alkyl group present inthe hole transport layer may interact with each other, thereby improvingeffects such as hole injectability.

In addition, when the solvent that disperses the quantum dot is along-chain hydrocarbon-based solvent, it is desirable that the number ofthe alkyl group in the polymer compound is small in terms of securing aresidual film ratio of the hole transport layer.

Therefore, as the alkyl group, a linear or branched C1 to C18 alkylgroup is more desirable. The alkyl group may be appropriately selectedaccording to the used quantum dot or the solvent that disperses thequantum dot.

Chemical Formula 108

From the viewpoint of further improving the effect of the presentdisclosure, in Chemical Formula (L2), the group (—NX₂) bound to Ar_(a)may be desirably a group of Group L2-B′. In Chemical Formula (L2), aplurality of the groups (—NX₂) bound to Ar_(a) may be the same ordifferent. In Group L2-B′, * represents a linking portion with Ar_(a) ofChemical Formula (L2).

Specific examples of the low molecular compound 2 may be a compoundrepresented by the following chemical formulae. The low molecularcompound 2 may be used alone or in a combination of two or more types.

The low molecular compound 2 may be synthesized by using a known organicsynthesis method.

Low Molecular Compounds 3 and 4

According to the preferred embodiment of the present disclosure, the lowmolecular material may include at least one of a low molecular compoundrepresented by Chemical Formula (L3) (hereinafter, also referred to as“low molecular compound 3”) and a low molecular compound represented byChemical Formula (L4) (hereinafter, also referred to as “low molecularcompound 4”). The low molecular compounds 3 and 4 are hole transportingmaterials and when used in combination with the polymer material, thelow molecular compounds 3 and 4 exist to enter the gap of the polymermaterial. Therefore, a more dense hole transport layer may be providedand the hole transport capability of the hole transport layer may beimproved. In addition, since the hole transport capability of the lowmolecular compounds 3 and 4 themselves, which are the hole transportingmaterials to be added, is imparted to the hole transport layer, aneffect of further improving hole transport properties may be obtained.

According to a more desirable embodiment, the low molecular material isat least one of the low molecular compound 3 and the low molecularcompound 4.

Hereinafter, the low molecular compound 3 and the low molecular compound4 are described.

Low Molecular Compound 3

The low molecular compound 3 is a compound represented by ChemicalFormula (L3).

In Chemical Formula (L3), R₁ to R₃ are independently a hydrogen atom, amonovalent hydrocarbon group, or a monovalent aromatic hydrocarbongroup. R₁, R₂, and R₃ may independently be the same or different. Inaddition, in Chemical Formula (L3), two adjacent R₁'s may be linked toeach other to form a ring. Herein, the monovalent hydrocarbon group mayinclude, for example, a linear or branched alkyl group, alkenyl group,and alkynyl group, and a cyclic alkyl group (cycloalkyl group), and thelike, but is not particularly limited thereto. The alkyl group may bedesirably a C1 to C20 linear or branched alkyl group. The alkyl groupmay be, for example, a methyl group, an ethyl group, an n-propyl group,an isopropyl group, an n-butyl group, an isobutyl group, a sec-butylgroup, a tert-butyl group, an n-pentyl group, an isopentyl group, atert-pentyl group, a neopentyl group, a 1,2-dimethylpropyl group, ann-hexyl group, an isohexyl group, a 1,3-dimethylbutyl group, a1-isopropylpropyl group, a 1,2-dimethylbutyl group, an n-heptyl group, a1,4-dimethylpentyl group, a 3-ethylpentyl group, a2-methyl-1-isopropylpropyl group, a 1-ethyl-3-methylbutyl group, ann-octyl group, a 2-ethylhexyl group, a 3-methyl-1-isopropylbutyl group,a 2-methyl-1-isopropylbutyl group, a 1-tert-butyl-2-methylpropyl group,an n-nonyl group, a 3,5,5-trimethylhexyl group, an n-decyl group, anisodecyl group, an n-undecyl group, a 1-methyldecyl group, an n-dodecylgroup, an n-tridecyl group, an n-tetradecyl group, an n-pentadecylgroup, an n-hexadecyl group, an n-heptadecyl group, or an n-octadecylgroup, but is not limited thereto.

The carbon number of the alkyl group is more desirably in the followingtype.

For example, when the ligand of the quantum dot is a long chainalkyl-containing compound such as oleic acid, oleylamine, ortrioctylphosphine, the compound included in the hole transport layer mayalso desirably include a compound having a long chain alkyl group. Thisis because the ligand of the quantum dot and the alkyl group present inthe hole transport layer may interact with each other, thereby improvingeffects such as hole injectability.

In addition, when the solvent that disperses the quantum dot is along-chain hydrocarbon-based solvent, it is desirable that the number ofthe alkyl group in the polymer compound is small in terms of securing aresidual film ratio of the hole transport layer.

Therefore, as the alkyl group, a linear or branched C1 to C18 alkylgroup is more desirable. The alkyl group may be appropriately selectedaccording to the used quantum dot or the solvent that disperses thequantum dot.

The alkenyl groups may be desirably a linear or branched C2 to C12alkenyl groups. Such an alkenyl group may include, but is not limitedto, for example, a vinyl group, an allyl group, a 1-propenyl group, a2-butenyl group, a 1,3-butathienyl group, a 2-pentenyl group, anisopropenyl group, and the like. The alkynyl group may be desirably alinear or branched C2 to C12 alkynyl group. Such an alkynyl group mayinclude, but is not limited to, for example, an ethynyl groups, apropargyl group, and the like. The cycloalkyl group may be desirably aC3 to C12 cycloalkyl group. Such a cycloalkyl group may include, but isnot limited to, for example, a cyclopropyl group, a cyclobutyl group, acyclopentyl group, a cyclohexyl group, and the like. In addition, themonovalent aromatic hydrocarbon group may include, for example, a C6 toC25 aromatic hydrocarbon group, and the like but is not particularlylimited thereto. C6 to C25 aromatic hydrocarbon group may include, forexample, a monovalent group derived from aromatic hydrocarbon such asbenzene (phenyl group), pentane, indene, naphthalene, anthracene,azulene, heptylene, acenaphthene, phenalene, fluorene, anthraquinoline,phenanthrene, biphenyl, terphenyl, tetraphenyl, pentaphenyl, hexaphenyl,pyrene, 9,9-diphenylfluorene, 9,9′-spirobi[fluorene], and the like, butare not limited thereto. Among them, from the viewpoint of furtherimproving the effect of the present disclosure, R₁ is independently ahydrogen atom or a C1 to C12 linear or branched alkyl group, a phenylgroup, or a biphenyl group, more desirably a C3 to C10 linear orbranched alkyl group, phenyl group or a biphenyl group, and particularlydesirably a C5 to C8 linear alkyl group or a phenyl group. In addition,from the viewpoint of further improving the effect of the presentdisclosure, R₂ to R₃ are independently a hydrogen atom or a C1 to C8linear or branched alkyl group, desirably hydrogen or a C1 to C3 linearalkyl group, and more desirably hydrogen.

That is, from the viewpoint of further improving the effect of thepresent disclosure, the following structure in which X₁ and X₂ ofChemical Formula (L3) are excluded (i.e., the following structure) maybe desirably of the group:

In the following description, “Alkyl” means “unsubstituted (i.e.,Alkyl=hydrogen atom) or substituted with an alkyl group”. Desirably,“Alkyl” means substitution with a C1 to C12 linear or branched alkylgroup. More desirably, “Alkyl” means substitution with a C5 to C8 linearalkyl group. In addition, “Alkyl” may be the same alkyl group or adifferent alkyl group. In the following structures, * represents alinking portion with an adjacent atom.

In Chemical Formula (L3), X₁ may be a group represented by hydrogen orChemical Formula (L3-a). In addition, X₂ is group represented byChemical Formula (L3-a). That is, the low molecular compound 3 has oneor two groups represented by Chemical Formula (L3-a). In ChemicalFormula (L3-a), “*” represents a portion at which X₁ or X₂ are linked tothe fluorene ring in Chemical Formula (L3)

In Chemical Formula (L3-a), R₄ to R₅ are independently hydrogen atom ormonovalent hydrocarbon group. A plurality, preferably adjacent R₄ to R₅may independently be the same or different. In addition, in ChemicalFormula (L3-a), adjacent groups R₄ to R₅ may be linked to each other toform a ring. Herein, specific examples of the monovalent hydrocarbongroup may be the same as definitions of R₁ to R₃ in Chemical Formula(L3), but are not particularly limited thereto. Among them, from theviewpoint of further improving the effect of the present disclosure, R₄to R₅ may independently be a hydrogen atom or a C1 to C12 linear orbranched alkyl group, and desirably a hydrogen atom or a C3 to C10linear or branched alkyl group.

In addition, in Chemical Formula (L3-a), l, m, and n are independentlyan integer of 0 to 3. From the viewpoint of further improving the effectof the present disclosure, I may be desirably an integer of 0 to 2, andmore desirably 0 or 1. In addition, from the viewpoint of furtherimproving the effect of the present disclosure, n and m may be desirablyan integer of 0 to 2, and more desirably 0 or 2.

In Chemical Formula (L3-a), as shown in the following low molecularcompound (L3-2), two phenyl groups at terminal ends may be linked toform a carbazole ring.

That is, from the viewpoint of further improving the effect of thepresent disclosure, the group represented by Chemical Formula (L3-a) maydesirably have a structure of Group L3-A. In Group L3-A, * represents alinking portion with an adjacent atom.

The low molecular compound 3 may desirably be a compound represented byany one of Chemical Formula (L3-1) to Chemical Formula (L3-10).

The low molecular compound 3 may be synthesized by using a known organicsynthesis method.

Low Molecular Compound 4

The low molecular compound 4 is a compound represented by ChemicalFormula (L4).

In Chemical Formula (L4), Y is a carbon atom (C) or a silicon atom (Si).

In Chemical Formula (L4), R₁, R₂, and R₃ are independently a hydrogenatom, a monovalent hydrocarbon group, or a monovalent aromatichydrocarbon group. R₁, R₂, and R₃ may independently be the same ordifferent. In addition, in Chemical Formula (L4), two R₁'s, preferablyadjacent, may be linked to each other to form a ring. Herein, since themonovalent hydrocarbon group and the monovalent aromatic hydrocarbongroup are not particularly limited, but may be the same as thedefinitions of R₁ to R₃ in Chemical Formula (L3), and thus thedescriptions thereof are omitted. Among them, from the viewpoint offurther improving the effect of the present disclosure, R₁ mayindependently be a hydrogen atom or a C1 to C18 linear or branched alkylgroup, a phenyl group, or a biphenyl group.

The carbon number of the alkyl group is more desirably in the followingtype.

For example, when the ligand of the quantum dot is a long chainalkyl-containing compound such as oleic acid, oleylamine, ortrioctylphosphine, the compound included in the hole transport layer mayalso desirably include a compound having a long chain alkyl group. Thisis because the ligand of the quantum dot and the alkyl group present inthe hole transport layer may interact with each other, thereby improvingeffects such as hole injectability.

In addition, when the solvent that disperses the quantum dot is along-chain hydrocarbon-based solvent, it is desirable that the number ofthe alkyl group in the polymer compound is small in terms of securing aresidual film ratio of the hole transport layer.

Therefore, as the alkyl group, a linear or branched C1 to C18 alkylgroup is more desirable. The alkyl group may be appropriately selectedaccording to the used quantum dot or the solvent that disperses thequantum dot.

In addition, from the viewpoint of further improving the effect of thepresent disclosure, R₂ and R₃ may independently be a hydrogen atom or aC1 to C18 linear or branched alkyl group.

From the viewpoint of further improving the effect of the presentdisclosure, the following structure in which X₁ and X₂ of ChemicalFormula (L4) are excluded (i.e., the following structure) may bedesirably the following structures:

In the following description, “Alkyl” means “unsubstituted (i.e.,Alkyl=hydrogen atom) or substituted with an alkyl group”. Desirably,“Alkyl” means substitution with a C1 to C8 linear or branched alkylgroup. More desirably, “Alkyl” means substitution with a C1 to C3 linearalkyl group. In addition, “Alkyl” may be the same alkyl group or adifferent alkyl group. In the following structures, * represents alinking portion with an adjacent atom.

In Chemical Formula (L4), X₁ may be hydrogen or a group represented byChemical Formula (L4-a). In addition, X₂ may be a group represented byChemical Formula (L4-a). That is, the low molecular compound 4 has oneor two groups represented by Chemical Formula (L4-a). In ChemicalFormula (L4-a), “*” represents a portion at which X₁ or X₂ are linked tobenzene ring (phenylene-) of Y—(R₁)₂(phenylene-)₂ in Chemical Formula(L4). In Chemical Formula (L4-a), the definitions of R₄ and R₅, l, m,and n may be the same as the definitions of R₄ and R₅, l, m, and n ofChemical Formula (L3-a), and thus the descriptions thereof are omitted.

The low molecular compound 3 may desirably be a compound represented byany one of Chemical Formula (L4)-1 to Chemical Formula (L4)-2.

The low molecular compound 4 may be synthesized by using a known organicsynthesis method.

Low Molecular Compounds 5 and 6

According to the preferred embodiment of the present disclosure, the lowmolecular material may include at least one of a low molecular compoundrepresented by Chemical Formula (L5) (hereinafter, also referred to as“low molecular compound 5”) and a low molecular compound represented byChemical Formula (L6) (hereinafter, also referred to as “low molecularcompound 6”). The low molecular compounds 5 and 6 are wide gapmaterials, and when used in combination with the polymer material, thelow molecular compounds 5 and 6 exist to enter the gap of the polymermaterial. Therefore, a more dense hole transport layer may be providedand the hole transport capability of the hole transport layer may beimproved. According to a more desirable embodiment, the low molecularmaterial is at least one of the low molecular compound 5 and the lowmolecular compound 6.

Hereinafter, the low molecular compound 5 and the low molecular compound6 are described.

Here, the wide gap material refers to a material having a HOMO-LUMOenergy gap of greater than or equal to about 3.3 eV. The HOMO-LUMOenergy gap is not particularly limited but desirably is less than orequal to about 4 eV. Within this range, the luminous efficiency andlight emitting life-span of the quantum dot EL device may be moreimproved.

Low Molecular Compound 5

The wide gap material may desirably include at least one low molecularcompound 5 represented by Chemical Formula (L5).

In Chemical Formula (L5),

m and n are independently an integer of 0 to 3,

R is independently a hydrogen atom, or a monovalent organic group or twoor more adjacent R's may be condensed or linked to each other to form aring,

X represents O, S, NR′, C(R″)₂, and

R′ and R″ are independently a hydrogen atom or a monovalent organicgroup.

In Chemical Formula (L5), the monovalent organic group constituting R isnot particularly limited. For example, it may be hydrogen, a cyanogroup, a substituted or unsubstituted C1 to C30 alkyl group, asubstituted or unsubstituted C1 to C30 alkoxy group, a substituted orunsubstituted C6 to C30 aryloxy group, an alkylamino group having asubstituted or unsubstituted C1 to C30 alkyl group, a substituted orunsubstituted C6 to C30 monovalent aromatic hydrocarbon ring group, or asubstituted or unsubstituted monovalent aromatic heterocyclic grouphaving 3 to 60 ring-forming atoms.

The C6 to C30 aromatic hydrocarbon ring group constituting R may be agroup derived from C6 to C30 hydrocarbon (aromatic hydrocarbon) ringshaving a carbon ring containing one or a plurality of aromatic rings. Inaddition, when the aromatic hydrocarbon ring group may include two ormore rings, two or more rings may be condensed with each other. One ormore hydrogen atoms present in these aromatic hydrocarbon ring groupsmay be substituted with a substituent.

The aromatic hydrocarbon ring constituting the aromatic hydrocarbon ringgroup is not particularly limited, but may specifically be benzene,pentalene, indene, naphthalene, anthracene, azulene, heptalene,acenaphthalene, phenalene, fluorene, phenanthrene, biphenyl,triphenylene, pyrene, chrysene, pycene, perylene, pentaphene, pentacene,tetraphene, hexaphene, hexacene, rubicene, trinaphthylene, heptaphene,and pyrantrene.

The monovalent aromatic heterocyclic group having 3 to 60 ring-formingatoms constituting R may be a group derived from a cycle (aromaticheterocycle) having 3 to 60 ring-forming atoms which includes at leastone aromatic ring having at least one heteroatom (for example, anitrogen atom (N), an oxygen atom (O), a phosphorus atom (P), or asulfur atom (S)) and a remaining ring atom that is a carbon atom (C). Inaddition, when the aromatic heterocyclic group includes two or morerings, two or more rings may be condensation with each other. It mayalso be substituted with one or more hydrogen atom substituents presentin these aromatic heterocyclic groups.

Herein, the number of ring-forming atoms represents the number of atomsconstituting the ring itself in a compound having a structure in whichthe atoms are bonded in a cyclic structure (for example, monocycle,condensed ring, ring cluster). When atoms that do not form a ring (forexample, hydrogen atoms that terminate the bonds of atoms thatconstitute the ring), or the rings is substituted by a substituent, theatoms included in the substituent are not included in the number ofring-forming atoms. For example, the carbazolyl group (substituted withcarbazole ring) has the number of ring-forming atoms of 13.

The aromatic heterocycle constituting aromatic heterocyclic group mayinclude, but is not particularly limited to, a π electron-deficientaromatic heterocycle, a π electron-excess aromatic heterocycle, πelectron-deficient-π electron-excess mixed aromatic heterocycle in whicha π electron-deficient aromatic heterocycle and a π electron excessaromatic heterocycle are mixed.

Examples of the π electron-deficient aromatic heterocycle may bepyridine, pyrazine, pyridazine, pyrimidine, triazine, quinoline,isoquinoline, quinoxaline, quinazoline, naphthyridine, acridine,phenazine, benzoquinoline, benzisoquinoline, phenanthridine,phenanthroline, benzoquinone, coumarin, anthraquinone, fluorenone, andthe like.

Examples of the π electron-excess aromatic heterocycle may be furan,thiophene, benzofuran, benzothiophene, dibenzofuran, dibenzothiophene,pyrrole, indole, carbazole, and the like.

Examples of the π electron-deficient-π electron-excess mixed aromaticheterocycle may be imidazole, benzimidazole, pyrazole, indazole,oxazole, isoxazole, benzoxazole, benzisoxazole, thiazole, isothiazole,benzothiazole, benzoisothiazole, imidazolinone, benzimidazolinone,imidazopyridine, imidazopyrimidine, imidazophenanthridine,benzimidazophenanthridine, azadibenzofuran, azacarbazole,azadibenzothiophene, diazadibenzofuran, diazacarbazole,diazadibenzothiophene, xanthone, and dioxantone.

The C1 to C30 alkyl group constituting R is not particularly limited.For example, it may be a C1 to C30 linear or branched alkyl group.Specifically, it may be a methyl group, an ethyl group, an n-propylgroup, a isopropyl group, an n-butyl group, an isobutyl group, asec-butyl group, a tert-butyl group, an n-pentyl group, an isopentylgroup, a tert-pentyl group, a neopentyl group, a 1,2-dimethylpropylgroup, an n-hexyl group, a isohexyl group, a 1,3-dimethylbutyl group, a1-isopropylpropyl group, a 1,2-dimethylbutyl group, an n-heptyl group, a1,4-dimethylpentyl group, 3-ethylpentyl group, a2-methyl-1-isopropylpropyl group, a 1-ethyl-3-methylbutyl group, ann-octyl group, a 2-ethylhexyl group, a 3-methyl-1-isopropylbutyl group,a 2-methyl-1-isopropylbutyl group, a 1-tert-butyl-2-methylpropyl group,an n-nonyl group, a 3,5,5-trimethylhexyl group, an n-decyl group, aisodecyl group, an n-undecyl group, a 1-methyldecyl group, an n-dodecylgroup, an n-tridecyl group, an n-tetradecyl group, an n-pentadecylgroup, an n-hexadecyl group, an n-heptadecyl group, an n-octadecylgroup, an n-nonadecyl group, an n-eicosyl group, an n-heneicosyl group,an n-docosyl group, an n-tricosyl group, and an n-tetracosyl group.

The carbon number of the alkyl group is more desirably in the followingtype.

For example, when the ligand of the quantum dot is a long chainalkyl-containing compound such as oleic acid, oleylamine, ortrioctylphosphine, the compound included in the hole transport layer mayalso desirably include a compound having a long chain alkyl group. Thisis because the ligand of the quantum dot and the alkyl group present inthe hole transport layer may interact with each other, thereby improvingeffects such as hole injectability.

In addition, when the solvent that disperses the quantum dot is along-chain hydrocarbon-based solvent, it is desirable that the number ofthe alkyl group in the polymer compound is small in terms of securing aresidual film ratio of the hole transport layer.

Therefore, as the alkyl group, a linear or branched C1 to C18 alkylgroup is more desirable. The alkyl group may be appropriately selectedaccording to the used quantum dot or the solvent that disperses thequantum dot.

The C1 to C30 alkoxy group constituting R is not particularly limited.For example, it may be a C1 to C30 linear or branched alkoxy group.Specifically, it may be a methoxy group, an ethoxy group, a propoxygroup, an isopropoxy group, a butoxy group, a pentyloxy group, ahexyloxy group, a heptyloxy group, an octyloxy group, a nonyloxy group,a decyloxy group, an undecyloxy group, a dodecyloxy group, a tridecyloxygroup, a tetradecyloxy group, a pentadecyloxy group, a hexadecyloxygroup, a heptadecyloxy group, an octadecyloxy group, a 2-ethylhexyloxygroup, a 3-ethylpentyloxy group, and the like.

The carbon number of the alkoxy group is more desirably in the followingtype.

For example, when the ligand of the quantum dot is a long chainalkyl-containing compound such as oleic acid, oleylamine, ortrioctylphosphine, the compound included in the hole transport layer mayalso desirably include a compound having a long chain alkoxy group. Thisis because the ligand of the quantum dot and the alkoxy group present inthe hole transport layer may interact with each other, thereby improvingeffects such as hole injectability.

In addition, when the solvent that disperses the quantum dot is along-chain hydrocarbon-based solvent, it is desirable that the number ofthe alkoxy group in the polymer compound is small in terms of securing aresidual film ratio of the hole transport layer.

Therefore, as the alkoxy group, a linear or branched C1 to C18 alkoxygroup is more desirable. These alkoxy groups may be appropriatelyselected according to the used quantum dot or the solvent that dispersesthe quantum dot.

The C6 to C30 aryloxy group constituting R is not particularly limitedFor example, it may be a C6 to C30 monocyclic or condensed polycyclicaryloxy group that may include a heteroatom. Specifically, it may be aphenoxy group, a 1-naphthyloxy group, a 2-naphthyloxy group, a2-azulenyloxy group, a 2-furanyloxy group, a 2-thienyloxy group, a2-indolyloxy group, a 3-indolyloxy group, a 2-benzofuryloxy group, and a2-benzothienyloxy group.

The alkylamino group having the C1 to C30 alkyl constituting R is notparticularly limited. For example, it may be an alkylamino group havinga linear or branched C1 to C30 alkyl group. Specifically, it may be anN-alkylamino group such as an N-methylamino group, an N-ethylaminogroup, an N-propylamino group, an N-isopropylamino group, anN-butylamino group, an N-isobutylamino group, an N-sec-butylamino group,an N-tert-butylamino group, an N-pentylamino group, or an N-hexylaminogroup, an N,N-dialkylamino group such as an N,N-dimethylamino group, anN-methyl-N-ethylamino group, an N,N-diethylamino group, anN,N-dipropylamino group, an N,N-diisopropylamino group, anN,N-dibutylamino group, an N,N-diisobutylamino group, anN,N-dipentylamino group, an N,N-dihexylamino group, and the like.

When the C1 to C30 alkyl group, C1 to C30 alkoxy group, C6 to C30aryloxy group, alkylamino group having the C1 to C30 alkyl group, cyanogroup, C6 to C30 monovalent aromatic hydrocarbon ring group, ormonovalent aromatic heterocyclic group having 3 to 60 ring-forming atomswhich constitutes R is further substituted with another substituent, thesubstituent is not particularly limited. Another substituent may be, forexample, the same as the substituent which may constitute R. That is, itmay be for example hydrogen, a cyano group, a substituted orunsubstituted, C1 to C30 alkyl group, C1 to C30 alkoxy group, C6 to C30aryloxy group, alkylamino group having a C1 to C30 alkyl group, C6 toC30 monovalent aromatic hydrocarbon ring group, or monovalent aromaticheterocyclic group having 3 to 60 ring-forming atoms. Since thedescription of another substituent is the same as that of R, thedescription is omitted.

Another substituent that further substitutes for another substituent, ornext another substituent that further substitutes for anothersubstituent is the same as another substituent that is described above.

In Chemical Formula (L5), R′ and R″ in NR′ and C(R″)₂ which mayconstitute X are not particularly limited. For example, they may behydrogen, a cyano group, a substituted or unsubstituted C1 to C30 alkylgroup, a substituted or unsubstituted C1 to C30 alkoxy group, asubstituted or unsubstituted C6 to C30 aryloxy group, a substituted orunsubstituted C1 to C30 amino group, a substituted or unsubstituted C6to C30 monovalent aromatic hydrocarbon ring group, or a substituted orunsubstituted monovalent aromatic heterocyclic group having 3 to 60ring-forming atoms.

The description of the monovalent organic group that may constitute R′and R″ is the same as that described in R, and thus the descriptionthereof is omitted.

Divalent organic groups which may constitute X other than NR′ and C(R″)₂are not particularly limited.

Here, in the compound represented by Chemical Formula (L5), it isdesirably that m and n are independently an integer of greater than orequal to 1 and less than or equal to 3. In addition, it is moredesirably that m and n are independently an integer of greater than orequal to 2 and less than or equal to 3, and more desirably 3.

The compound represented by Chemical Formula (L5) is desirably acompound represented by Chemical Formula (L5-A).

In Chemical Formula (L5-A), R and X are the same as in Chemical Formula(L5).

In Chemical Formula (L5) and Chemical Formula (L5-A), R mayindependently be a hydrogen atom, a cyano group, an unsubstituted C1 toC30 alkyl group, an unsubstituted C1 to C30 alkoxy group, anunsubstituted C6 to C30 aryloxy group, an unsubstituted alkylamino grouphaving a C1 to C30 alkyl group, an unsubstituted C6 to C30 monovalentaromatic hydrocarbon ring group, or an unsubstituted monovalent aromaticheterocyclic group having 3 to 60 ring-forming atoms. In addition, R mayindependently be a hydrogen atom, a cyano group, an unsubstituted C1 toC30 alkyl group, an unsubstituted C1 to C30 alkoxy group, anunsubstituted C6 to C30 aryloxy group, or an unsubstituted alkylaminogroup having a C1 to C30 alkyl group. R may be all hydrogen atoms.

In Chemical Formula (L5) and Chemical Formula (L5-A), R′ may behydrogen, a cyano group, an unsubstituted C1 to C30 alkyl group, anunsubstituted C1 to C30 alkoxy group, an unsubstituted C6 to C30 aryloxygroup, an unsubstituted C1 to C30 amino group, an unsubstituted C6 toC30 monovalent aromatic hydrocarbon ring group, or an unsubstitutedmonovalent aromatic heterocyclic group having 3 to 60 ring-formingatoms. In addition, R′ may independently be a hydrogen atom, a cyanogroup, an unsubstituted C1 to C30 alkyl group, an unsubstituted C1 toC30 alkoxy group, an unsubstituted C6 to C30 aryloxy group, or anunsubstituted alkylamino group having a C1 to C30 alkyl group. R′ may beall hydrogen atoms.

In Chemical Formula (L5) and Chemical Formula (L5-A), R″ mayindependently be a hydrogen atom, a cyano group, an unsubstituted C1 toC30 alkyl group, an unsubstituted C1 to C30 alkoxy group, anunsubstituted C6 to C30 aryloxy group, an unsubstituted alkylamino grouphaving a C1 to C30 alkyl group, an unsubstituted C6 to C30 monovalentaromatic hydrocarbon ring group, or an unsubstituted monovalent aromaticheterocyclic group having 3 to 60 ring-forming atoms. In addition, R″may independently be a hydrogen atom, a cyano group, an unsubstituted C1to C30 alkyl group, an unsubstituted C1 to C30 alkoxy group, anunsubstituted C6 to C30 aryloxy group, or an unsubstituted C1 to C30amino group. R″ may be all hydrogen atoms.

The carbon number of the alkyl group is more desirably in the followingtype.

For example, when the ligand of the quantum dot is a long chainalkyl-containing compound such as oleic acid, oleylamine, ortrioctylphosphine, the compound included in the hole transport layer mayalso desirably include a compound having a long chain alkyl group. Thisis because the ligand of the quantum dot and the alkyl group present inthe hole transport layer may interact with each other, thereby improvingeffects such as hole injectability.

In addition, when the solvent that disperses the quantum dot is along-chain hydrocarbon-based solvent, it is desirable that the number ofthe alkyl group in the polymer compound is small in terms of securing aresidual film ratio of the hole transport layer.

Therefore, as the alkyl group, a linear or branched C1 to C18 alkylgroup is more desirable. The alkyl group may be appropriately selectedaccording to the used quantum dot or the solvent that disperses thequantum dot.

The carbon number of the alkoxy group is more desirably in the followingtype.

For example, when the ligand of the quantum dot is a long chainalkyl-containing compound such as oleic acid, oleylamine, ortrioctylphosphine, the compound included in the hole transport layer mayalso desirably include a compound having a long chain alkoxy group. Thisis because the ligand of the quantum dot and the alkoxy group present inthe hole transport layer may interact with each other, thereby improvingeffects such as hole injectability.

In addition, when the solvent that disperses the quantum dot is along-chain hydrocarbon-based solvent, it is desirable that the number ofthe alkoxy group in the polymer compound is small in terms of securing aresidual film ratio of the hole transport layer.

Therefore, as the alkoxy group, a linear or branched C1 to C18 alkoxygroup is more desirable. These alkoxy groups may be appropriatelyselected according to the used quantum dot or the solvent that dispersesthe quantum dot.

In Chemical Formula (L5) and Chemical Formula (L5-A), X may be desirablyO, S, NR′, or C(R″)₂. Further, X may be desirably O or S, and moredesirably S.

Hereinafter, the low molecular compound 5 is specifically exemplified.The present disclosure is not limited to these specific examples.

Among these, the compound 11 may particularly be desirable.

A method of preparing the low molecular compound 5 is not particularlylimited, and various preparing methods including known synthesis methodsmay be used.

Low Molecular Compound 6

The wide gap material may desirably include at least one low molecularcompound 6 represented by Chemical Formula (L6).

In Chemical Formula (L6),

m and n are independently an integer of 0 to 3, and

R is independently a hydrogen atom, or a monovalent organic group.

In Chemical Formula (L6), two or more R's may be condensed or linked toeach other to form a ring.

In Chemical Formula (L6), the monovalent organic group constituting R isnot particularly limited. For example, it may be hydrogen, a cyanogroup, a substituted or unsubstituted C1 to C30 alkyl group, asubstituted or unsubstituted C1 to C30 alkoxy group, a substituted orunsubstituted C6 to C30 aryloxy group, a substituted or unsubstitutedalkylamino group having a C1 to C30 alkyl group, a substituted orunsubstituted C6 to C30 monovalent aromatic hydrocarbon ring group, or asubstituted or unsubstituted monovalent aromatic heterocyclic grouphaving 3 to 60 ring-forming atoms.

The C6 to C30 aromatic hydrocarbon ring group constituting R may be agroup derived from C6 to C30 hydrocarbon (aromatic hydrocarbon) ringshaving a carbon ring containing one or a plurality of aromatic rings. Inaddition, when the aromatic hydrocarbon ring group may include two ormore rings, two or more rings may be condensed with each other. One ormore hydrogen atoms present in these aromatic hydrocarbon ring groupsmay be substituted with a substituent.

The aromatic hydrocarbon ring constituting the aromatic hydrocarbon ringgroup is not particularly limited, but may specifically be benzene,pentalene, indene, naphthalene, anthracene, azulene, heptalene,acenaphthalene, phenalene, fluorene, phenanthrene, biphenyl,triphenylene, pyrene, chrysene, pycene, perylene, pentaphene, pentacene,tetraphene, hexaphene, hexacene, rubicene, trinaphthylene, heptaphene,and pyrantrene.

The monovalent aromatic heterocyclic group having 3 to 60 ring-formingatoms constituting R may be a group derived from a cycle (aromaticheterocycle) having 3 to 60 ring-forming atoms which includes at leastone aromatic ring having at least one heteroatom (for example, anitrogen atom (N), an oxygen atom (O), a phosphorus atom (P), or asulfur atom (S)) and a remaining ring atom that is a carbon atom (C). Inaddition, when the aromatic heterocyclic group includes two or morerings, two or more rings may be condensation with each other. It mayalso be substituted with one or more hydrogen atom substituents presentin these aromatic heterocyclic groups.

Herein, the number of ring-forming atoms represents the number of atomsconstituting the ring itself in a compound having a structure in whichthe atoms are bonded in a cyclic structure (for example, monocycle,condensed ring, ring cluster). When atoms that do not form a ring (forexample, hydrogen atoms that terminate the bonds of atoms thatconstitute the ring), or the rings is substituted by a substituent, theatoms included in the substituent are not included in the number ofring-forming atoms. For example, the carbazolyl group (substituted withcarbazole ring) has the number of ring-forming atoms of 13.

The aromatic heterocycle constituting aromatic heterocyclic group mayinclude, but is not particularly limited to, a π electron-deficientaromatic heterocycle, a π electron-excess aromatic heterocycle, a πelectron-deficient-π electron-excess mixed aromatic heterocycle in whicha π electron-deficient aromatic heterocycle and a π electron excessaromatic heterocycle are mixed.

Examples of the π electron-deficient aromatic heterocycle may bepyridine, pyrazine, pyridazine, pyrimidine, triazine, quinoline,isoquinoline, quinoxaline, quinazoline, naphthyridine, acridine,phenazine, benzoquinoline, benzisoquinoline, phenanthridine,phenanthroline, benzoquinone, coumarin, anthraquinone, fluorenone, andthe like.

Examples of the π electron-excess aromatic heterocycle may be furan,thiophene, benzofuran, benzothiophene, dibenzofuran, dibenzothiophene,pyrrole, indole, carbazole, and the like.

Examples of the π electron-deficient-π electron-excess mixed aromaticheterocycle may be imidazole, benzimidazole, pyrazole, indazole,oxazole, isoxazole, benzoxazole, benzisoxazole, thiazole, isothiazole,benzothiazole, benzisothiazole, imidazolinone, benzimidazolinone,imidazopyridine, imidazopyrimidine, imidazophenanthridine,benzimidazophenanthridine, azadibenzofuran, azacarbazole,azadibenzothiophene, diazadibenzofuran, diazacarbazole,ziazadibenzothiophene, xanthone, and dioxantone.

In a group formed by linking the two or more C6 to C30 monovalentaromatic hydrocarbon ring groups constituting R or monovalent aromaticheterocyclic groups having 3 to 60 ring-forming atoms constituting R, bya single bond, the C6 to C30 monovalent aromatic hydrocarbon ring groupand the monovalent aromatic heterocyclic group having 3 to 60ring-forming atoms are the same as described above, and thus thedescription thereof is omitted.

The C1 to C30 alkyl group constituting R is not particularly limited.For example, it may be a C1 to C30 linear or branched alkyl group.Specifically, it may be a methyl group, an ethyl group, an n-propylgroup, a isopropyl group, an n-butyl group, an isobutyl group, asec-butyl group, a tert-butyl group, an n-pentyl group, an isopentylgroup, a tert-pentyl group, a neopentyl group, a 1,2-dimethylpropylgroup, an n-hexyl group, a isohexyl group, a 1,3-dimethylbutyl group, a1-isopropylpropyl group, a 1,2-dimethylbutyl group, an n-heptyl group, a1,4-dimethylpentyl group, 3-ethylpentyl group, a2-methyl-1-isopropylpropyl group, a 1-ethyl-3-methylbutyl group, ann-octyl group, a 2-ethylhexyl group, a 3-methyl-1-isopropylbutyl group,a 2-methyl-1-isopropylbutyl group, a 1-tert-butyl-2-methylpropyl group,an n-nonyl group, a 3,5,5-trimethylhexyl group, an n-decyl group, aisodecyl group, an n-undecyl group, a 1-methyldecyl group, an n-dodecylgroup, an n-tridecyl group, an n-tetradecyl group, an n-pentadecylgroup, an n-hexadecyl group, an n-heptadecyl group, an n-octadecylgroup, an n-nonadecyl group, an n-eicosyl group, an n-heneicosyl group,an n-docosyl group, an n-tricosyl group, and an n-tetracosyl group.

The carbon number of the alkyl group is more desirably in the followingtype.

For example, when the ligand of the quantum dot is a long chainalkyl-containing compound such as oleic acid, oleylamine, ortrioctylphosphine, the compound included in the hole transport layer mayalso desirably include a compound having a long chain alkyl group. Thisis because the ligand of the quantum dot and the alkyl group present inthe hole transport layer may interact with each other, thereby improvingeffects such as hole injectability.

In addition, when the solvent that disperses the quantum dot is along-chain hydrocarbon-based solvent, it is desirable that the number ofthe alkyl group in the polymer compound is small in terms of securing aresidual film ratio of the hole transport layer.

Therefore, as the alkyl group, a linear or branched C1 to C18 alkylgroup is more desirable. The alkyl group may be appropriately selectedaccording to the used quantum dot or the solvent that disperses thequantum dot.

The C1 to C30 alkoxy group that may form R is not particularly limited.For example, it may be C1 to C30 linear or branched alkoxy group.Specifically, it may be a methoxy group, an ethoxy group, a propoxygroup, an isopropoxy group, a butoxy group, a pentyloxy group, ahexyloxy group, a heptyloxy group, an octyloxy group, a nonyloxy group,a decyloxy group, an undecyloxy group, a dodecyloxy group, a tridecyloxygroup, a tetradecyloxy group, a pentadecyloxy group, a hexadecyloxygroup, a heptadecyloxy group, an octadecyloxy group, a 2-ethylhexyloxygroup, a 3-ethylpentyloxy group, and the like.

The carbon number of the alkoxy group is more desirably in the followingtype.

For example, when the ligand of the quantum dot is a long chainalkyl-containing compound such as oleic acid, oleylamine, ortrioctylphosphine, the compound included in the hole transport layer mayalso desirably include a compound having a long chain alkoxy group. Thisis because the ligand of the quantum dot and the alkoxy group present inthe hole transport layer may interact with each other, thereby improvingeffects such as hole injectability.

In addition, when the solvent that disperses the quantum dot is along-chain hydrocarbon-based solvent, it is desirable that the number ofthe alkoxy group in the polymer compound is small in terms of securing aresidual film ratio of the hole transport layer.

Therefore, as the alkoxy group, a linear or branched C1 to C18 alkoxygroup is more desirable. These alkoxy groups may be appropriatelyselected according to the used quantum dot or the solvent that dispersesthe quantum dot.

The C6 to C30 aryloxy group constituting R is not particularly limited.For example, it may be a C6 to C30 monocyclic or condensed polycyclicaryloxy group that may include a heteroatom. Specifically, it may be aphenoxy group, a 1-naphthyloxy group, a 2-naphthyloxy group, a2-azulenyloxy group, a 2-furanyloxy group, a 2-thienyloxy group, a2-indolyloxy group, a 3-indolyloxy group, a 2-benzofuryloxy group, and a2-benzothienyloxy group.

The alkylamino group having the C1 to C30 alkyl group constituting R isnot particularly limited. For example, it may be an alkylamino grouphaving a linear or branched C1 to C30 alkyl group. Specifically, it maybe an N-alkylamino group such as an N-methylamino group, an N-ethylaminogroup, an N-propylamino group, an N-isopropylamino group, anN-butylamino group, an N-isobutylamino group, an N-sec-butylamino group,an N-tert-butylamino group, an N-pentylamino group, or an N-hexylaminogroup, an N,N-dialkylamino group such as an N,N-dimethylamino group, anN-methyl-N-ethylamino group, an N,N-diethylamino group, anN,N-dipropylamino group, an N,N-diisopropylamino group, anN,N-dibutylamino group, an N,N-diisobutylamino group, anN,N-dipentylamino group, an N,N-dihexylamino group, and the like.

When the C1 to C30 alkyl group, C1 to C30 alkoxy group, C6 to C30aryloxy group, alkylamino group having the C1 to C30 alkyl group, C6 toC30 monovalent aromatic hydrocarbon ring group, or monovalent aromaticheterocyclic group having 3 to 60 ring-forming atoms which constitutes Ris further substituted with another substituent, the substituent is notparticularly limited. Another substituent may be, for example, the sameas the substituent which may constitute R. That is, it may be forexample hydrogen, a cyano group, a substituted or unsubstituted, C1 toC30 alkyl group, C1 to C30 alkoxy group, C6 to C30 aryloxy group, C1 toC30 amino group, C6 to C30 monovalent aromatic hydrocarbon ring group,or monovalent aromatic heterocyclic group having 3 to 60 ring-formingatoms. Since the description of another substituent is the same as thatof R, the description is omitted.

Subsequent substituents that substitute for groups present in othersubstituents, such as another substituent that further substitutes foranother substituent, or next another substituent that furthersubstitutes for another substituent, are also the same as anothersubstituent that is described above.

The compound represented by Chemical Formula (L6) may desirably be acompound represented by Chemical Formula (L6-A), Chemical Formula(L6-B), Chemical Formula (L6-C), or Chemical Formula (L6-D).

In Chemical Formula (L6-A), Chemical Formula (L6-B), Chemical Formula(L6-C), and Chemical Formula (L6-D), R is the same as Chemical Formula(L6), R′ may independently be a hydrogen atom, a cyano group, asubstituted or unsubstituted C1 to C30 alkyl group, a substituted orunsubstituted C1 to C30 alkoxy group, a substituted or unsubstituted C6to C30 aryloxy group, or a substituted or unsubstituted alkylamino grouphaving a C1 to C30 alkyl group.

In Chemical Formula (L6), Chemical Formula (L6-A), Chemical Formula(L6-B), Chemical Formula (L6-C), and Chemical Formula (L6-D), R mayindependently be a hydrogen atom, a cyano group, an unsubstituted C1 toC30 alkyl group, an unsubstituted C1 to C30 alkoxy group, anunsubstituted C6 to C30 aryloxy group, an unsubstituted C1 to C30 aminogroup, an unsubstituted C6 to C30 monovalent aromatic hydrocarbon ringgroup, or unsubstituted monovalent aromatic heterocyclic group having 3to 60 ring-forming atoms. In addition, it is more desirably that R isall hydrogen atoms.

In Chemical Formula (L6-A), Chemical Formula (L6-B), Chemical Formula(L6-C), and Chemical Formula (L6-D), R′ may independently be a cyanogroup, an unsubstituted C1 to C30 alkyl group, an unsubstituted C1 toC30 alkoxy group, an unsubstituted C6 to C30 aryloxy group, or anunsubstituted alkylamino group having a C1 to C30 alkyl group. Inaddition, it is more desirably that R′ is all hydrogen atoms.

The carbon number of the alkyl group is more desirably in the followingtype.

For example, when the ligand of the quantum dot is a long chainalkyl-containing compound such as oleic acid, oleylamine, ortrioctylphosphine, the compound included in the hole transport layer mayalso desirably include a compound having a long chain alkyl group. Thisis because the ligand of the quantum dot and the alkyl group present inthe hole transport layer may interact with each other, thereby improvingeffects such as hole injectability.

In addition, when the solvent that disperses the quantum dot is along-chain hydrocarbon-based solvent, it is desirable that the number ofthe alkyl group in the polymer compound is small in terms of securing aresidual film ratio of the hole transport layer.

Therefore, as the alkyl group, a linear or branched C1 to C18 alkylgroup is more desirable. The alkyl group may be appropriately selectedaccording to the used quantum dot or the solvent that disperses thequantum dot.

The carbon number of the alkoxy group is more desirably in the followingtype.

For example, when the ligand of the quantum dot is a long chainalkyl-containing compound such as oleic acid, oleylamine, ortrioctylphosphine, the compound included in the hole transport layer mayalso desirably include a compound having a long chain alkoxy group. Thisis because the ligand of the quantum dot and the alkoxy group present inthe hole transport layer may interact with each other, thereby improvingeffects such as hole injectability.

In addition, when the solvent that disperses the quantum dot is along-chain hydrocarbon-based solvent, it is desirable that the number ofthe alkoxy group in the polymer compound is small in terms of securing aresidual film ratio of the hole transport layer.

Therefore, as the alkoxy group, a linear or branched C1 to C18 alkoxygroup is more desirable. These alkoxy groups may be appropriatelyselected according to the used quantum dot or the solvent that dispersesthe quantum dot.

Among the compounds represented by Chemical Formula (L6-A), ChemicalFormula (L6-B), Chemical Formula (L6-C) and Chemical Formula (L6-D), thecompound represented by Chemical Formula (L6-C) may be more desirable.

The present disclosure specifically illustrates the compound representedby Chemical Formula (L6), but the present disclosure is not limited tothese specific examples.

Among these, the compound 1 may particularly be desirable.

A method of preparing the low molecular compound 6 is not particularlylimited, and various preparing methods including known synthesis methodsmay be used.

A weight ratio of the polymer material and the low molecular material inthe hole transport layer is not particularly limited. However, from theviewpoint of obtaining the effect of the present disclosure moreefficiently, a content ratio of the polymer material may be greater thanabout 60 weight percent and less than about 100 weight percent based ona total amount, 100 weight percent of the polymer material and the lowmolecular material. In addition, the content ratio of the polymermaterial is desirably greater than about 60 weight percent and less thanor equal to about 95 weight percent, and particularly greater than orequal to about 70 weight percent and less than or equal to about 90weight percent.

A combination of the polymer material and the low molecular material isnot particularly limited. For example, the polymer compound 1 and thelow molecular compound 1 may be combined. The polymer compound 1 and thelow molecular compound 1 have similar structures.

Therefore, the hole transport layer including such a combination ofcompounds may become more dense, and thus may improve density and holetransport capability of the hole transport layer. As a result, luminousefficiency and light emitting life-span of the quantum dot EL device maybe more improved.

Quantum Dot Electroluminescence Device

Hereinafter, referring to FIG. 1, the quantum dot electroluminescencedevice (quantum dot EL device) according to the present embodiment isdescribed in detail. FIG. 1 is a schematic view showing a quantum dot ELdevice according to the present embodiment. As shown in FIG. 1, thequantum dot EL device 100 according to the present embodiment includes asubstrate 110, a first electrode 120 disposed on the substrate 110, ahole injection layer 130 disposed on the first electrode 120, a holetransport layer 140 disposed on the hole injection layer 130, a lightemitting layer 150 disposed on hole transport layer 140, an electrontransport layer 160 disposed on light emitting layer 150, an electroninjection layer 170 disposed on electron transport layer 160, and asecond electrode 180 disposed on the electron injection layer 170. Thepolymer material and low molecular material of the present embodimentare included in the hole transport layer 140.

The hole transport layer including the polymer material and the lowmolecular material of the present embodiment is desirably formed by asolution coating method. Specifically, it may be formed by a solutioncoating method such as a spin coating method, a casting method, a microgravure coating method, a gravure coating method, a bar coating method,a roll coating method, a wire bar coating method, a dip coating method,a spray coating method, a screen printing method, a flexographicprinting method, an offset printing method, an inkjet printing method,and the like.

As the solvent used in the solution coating method, any solvent may beused as long as it is capable of dissolving the polymer material and thelow molecular material, and the solvent may be appropriately selectedaccording to types of the used compounds. For example, the solvent maybe one or more of toluene, xylene, ethylbenzene, diethylbenzene,mesitylene, propylbenzene, cyclohexylbenzene, dimethoxybenzene, anisole,ethoxytoluene, phenoxytoluene, isopropylbiphenyl, dimethylanisole,phenyl acetate, phenyl propionate, methyl benzoate, ethyl benzoate,cyclohexane, and the like. An amount of the solvent used is notparticularly limited, but considering the ease of application,concentrations of the polymer material and the low molecular materialmay desirably be greater than or equal to about 0.1 weight percent andless than or equal to about 10 weight percent. More desirably, theconcentrations of the polymer material and the low molecular materialmay be greater than or equal to about 0.5 weight percent and less thanor equal to about 5 weight percent.

In addition, a ratio of contents of the polymer material and the lowmolecular material in a coating liquid (coating liquid for the holetransport layer formation) may be adjusted to obtain a desired contentratio in the hole transport layer.

After applying the coating liquid (coating liquid for forming the holetransport layer) and forming a film, the hole transport layer may beformed by heating and drying the film.

The conditions of the heating and drying are not particularly limited,but the heating and drying temperature may be desirably greater than orequal to about 50° C. and less than or equal to about 300° C., and moredesirably greater than or equal to about 100° C. and less than or equalto about 200° C. In addition, the heating and drying time may desirablybe 5 minutes or more and 240 minutes or less, and desirably greater thanor equal to about 20 minutes and less than or equal to about 60 minutes.By carrying out the heating and drying under these conditions, the holetransport layer may be formed.

Methods of forming layers other than the hole transport layer includingthe polymer material and the low molecular material of the presentdisclosure are not particularly limited. Such layers may be formed by,for example, a vacuum deposition method, or may be formed by a solutioncoating method.

The substrate 110 may be a substrate used in a general quantum dot ELdevice. For example, the substrate 110 may be a semiconductor substratesuch as a glass substrate, a silicon substrate, and the like, or atransparent plastic substrate.

On the substrate 110, a first electrode 120 is formed. The firstelectrode 120 is specifically a positive electrode, and is formed by amaterial having a large work function among a metal, an alloy, or aconductive compound. For example, the first electrode 120 may be formedas a transmissive electrode by indium tin oxide (In₂O₃—SnO₂: ITO),indium zinc oxide (In₂O₃—ZnO), tin oxide (SnO₂), zinc oxide (ZnO) or thelike due to improved transparency and conductivity. The first electrode120 may be formed as a reflective electrode by laminating magnesium(Mg), aluminum (Al), or the like on the transparent conductive layer.

On the first electrode 120, a hole injection layer 130 is formed. Thehole injection layer 130 is a layer that facilitates injection of holesfrom the first electrode 120, and may be formed to have a thickness ofspecifically greater than or equal to about 10 nm and less than or equalto about 1000 nm, and more specifically greater than or equal to about10 nm and less than or equal to about 100 nm.

The hole injection layer 130 may include a known hole injectionmaterial. The known hole injection material may include, for example,triphenylamine-containing polyetherketone (TPAPEK),4-isopropyl-4′-methyldiphenyl iodonium tetrakis(pentafluorophenyl)borate(PPBI),N,N′-diphenyl-N,N′-bis-[4-(phenyl-m-tolyl-amino)-phenyl]-biphenyl-4,4′-diamine(DNTPD), copper phthalocyanine,4,4′,4″-tris(3-methylphenylphenylamino)triphenylamine (m-MTDATA),N,N′-di(1-naphthyl)-N,N′-diphenylbenzidine (NPB),4,4′,4″-tris(diphenylamino)triphenylamine (TDATA),4,4′,4″-tris(N,N-2-naphthylphenylamino)triphenylamine (2-TNATA),polyaniline/dodecylbenzenesulphonic acid,poly(3,4-ethylenedioxythiophene)/poly(4-styrenesulfonate) (PEDOT-PSS),or polyaniline/10-camphorsulfonic acid, and the like.

On the hole injection layer 130, a hole transport layer 140 is formed.The hole transport layer 140 is a layer having a function oftransporting holes, and may be formed with a thickness of, for example,greater than or equal to about 10 nm and less than or equal to about 150nm. The hole transport layer 140 may include the polymer material andthe low molecular material of the present embodiment.

In addition to the polymer material and the low molecular material ofthe present embodiment, the hole transport layer 140 may include a knownhole transporting material. The known hole transporting material mayinclude, for example, 1,1-bis[(di-4-tolylamino) phenyl] cyclohexane(TAPC), a carbazole derivative such as N-phenylcarbazole,polyvinylcarbazole, and the like, N,N′-bis(3-methylphenyl)-N,N′-diphenyl-[1,1-biphenyl]-4,4′-diamine (TPD),4,4′,4″-tris(N-carbazolyl) triphenylamine (TCTA), orN,N′-di(1-naphthyl)-N,N′-diphenylbenzidine (NPB).

On the hole transport layer 140, a light emitting layer 150 is formed.The light emitting layer 150 is a layer that emits light byfluorescence, phosphorescence, and the like, and is formed using avacuum deposition method, a spin coating method, an inkjet printingmethod, or the like. The light emitting layer 150 may be formed with athickness of, for example, about 10 nm to about 60 nm, and morespecifically about 20 nm to about 50 nm. As the light emitting materialof the light emitting layer 150 in the present embodiment, semiconductornanoparticles (quantum dot) may be used.

Herein, in the case of forming the light emitting layer by a solutioncoating method such as a spin coating method, as a solvent of thedispersion for forming the light emitting layer including quantum dots,there is no particular limitation, but a poor solvent for the holetransport layer is desirably used. By using a poor solvent, the mixingof the low molecular material in the hole transport layer into the lightemitting layer may be further prevented. In addition, it is possible toconstruct a quantum dot EL device having a designed film thickness withgood reproducibility. In addition, the smoothness of the hole transportlayer surface is improved, and non-uniformity of the light emittingsurface and an occurrence of leakage current may be suppressed.Therefore, the quantum dot electroluminescence device of the presentdisclosure has improved luminous efficiency and light emittinglife-span.

Examples of the porous solvent may include a carbon-basedhydrocarbon-based solvent such as hexane, cyclohexane, heptane, octane,nonane, decane, undecane, and the like, an alcohol based solvent such asmethanol, ethanol, isopropyl alcohol, butanol, and the like. These poorsolvents may be used alone or in combination of two or more types as amixed solvent. In addition, depending on the adjustment of the solventviscosity and the like, it may be used in combination with a solventwhich becomes a good solvent as long as no film mixing occurs.

The light emitting layer is not particularly limited, and may include aknown quantum dot material(s). Among them, a quantum dot material havinga core-shell structure is desirable.

In the light emitting layer, a plurality of semiconductor nanoparticles(quantum dots) may be arranged in a monolayer or plural layer. Herein,the semiconductor nanoparticles (quantum dots) may be particles ofpredetermined sizes that have a quantum confinement effect. The diameterof the semiconductor nanoparticles (quantum dots) is not particularlylimited but is greater than or equal to about 1 nm and less than orequal to about 10 nm.

The semiconductor nanoparticles (quantum dots) arranged in the lightemitting layer may be synthesized by a wet chemical process, an organicmetal chemical deposition process, a molecular beam epitaxy process, oranother similar process. Among them, the wet chemical process is amethod of growing a particle by putting a precursor material in anorganic solvent.

In the wet chemistry process, when crystals grow, the organic solventnaturally coordinates to the surface of the quantum dot crystals andacts as a dispersing agent, thereby controlling the growth of thecrystals. For this reason, in the wet chemical process, compared withgas phase deposition methods, such as metal organic chemical vapordeposition (MOCVD) and molecular beam epitaxy (MBE), growth ofsemiconductor nanoparticles may be easily controlled at a low cost.

The semiconductor nanoparticles (quantum dots) may adjust energybandgaps by adjusting their sizes, so that light of various wavelengthsmay be obtained from the light emitting layer (quantum dot lightemitting layer). Thus, a plurality of differently sized quantum dots mayembody a display that discharges (or emits) light of multiplewavelengths. The sizes of the quantum dots may be selected to emit red,green, and blue light to form a color display. In addition, the sizes ofthe quantum dots may be combined so that various color lights emit whitelight.

The semiconductor nanoparticles (quantum dots) of the present disclosurehave core-shell structures. A material which constitutes a core portionmay be semiconductor material of a Group II-VI semiconductor compound; aGroup III-V semiconductor compound; a Group IV-VI semiconductorcompound; a Group IV element or compound; or a combination thereof.

Specifically, the semiconductor nanoparticles (quantum dots) of thepresent disclosure may be as follows.

The Group II-VI semiconductor compound is not particularly limited, butincludes, for example, a binary compound of CdSe, CdTe, ZnS, ZnSe, ZnTe,ZnO, HgS, HgSe, HgTe, or a mixture thereof; a ternary compound of CdSeS,CdSeTe, CdSTe, ZnSeS, ZnTeSe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS,CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, or aquaternary compound of CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe,CdHgSTe, HgZnSeS, HgZnSeTe, HgZnSTe, or a mixture thereof.

The Group III-V semiconductor compound is not particularly limited, butincludes, for example, a binary compound of GaN, GaP, GaAs, GaSb, AlN,AlP, AlAs, AlSb, InN, InP, InAs, InSb, or a mixture thereof; a ternarycompound of GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs,AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, GaAlNP, or a mixture thereof;or a quaternary compound of GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP,GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs,InAlPSb, or a mixture thereof.

The Group IV-VI semiconductor compound is not particularly limited, butincludes, for example, a binary compound of SnS, SnSe, SnTe, PbS, PbSe,PbTe, or a mixture thereof; a ternary compound of SnSeS, SnSeTe, SnSTe,PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, or a mixture thereof; or aquaternary compound of SnPbSSe, SnPbSeTe, SnPbSTe, or a mixture thereof.

The Group IV element or compound is not particularly limited, butincludes, for example, a single element of Si, Ge, or a mixture thereof;and a binary compound of SiC, SiGe, or a mixture thereof.

In the core-shell structure of the semiconductor nanoparticles (quantumdots) of the present disclosure, different materials may be included.The material constituting each core and shell may be made of differentsemiconductor compounds. However, an energy bandgap of the material ofthe shell portion is desirably larger than an energy bandgap of thematerial of the core portion.

The material desirably used in the shell portion may depend on energybandgaps of the material of the core portion used, but there are forexample, ZnS, ZnSe, or ZnSe/ZnS.

The shell portion does not have to completely cover the whole surface ofthe core portion, and may be cover at least a portion of the coreportion as long as there is no damage caused by the core portion beingpartially exposed. In addition, the core-shell structure may form agradient structure (tilt structure) from two or more types of compounds.

For example, a process of producing a quantum dot having a core(CdSe)-shell (ZnS) structure is described. First, crystals are formed byinjecting core (CdSe) precursor materials of (CH₃)₂Cd (dimethylcadmium), TOPSe (trioctylphosphine selenide) and the like into anorganic solvent using TOPO (trioctylphosphine oxide) as a surfactant. Atthis time, after maintaining a certain time at high temperature so thatthe crystals grow to a certain size, the precursor materials of theshell (ZnS) are injected, to form a shell on the surface of the corealready generated. As a result, a quantum dot of CdSe/ZnS capped withTOPO may be produced. In addition, by ligand exchange with oleic acid, aquantum dot of CdSe/ZnS capped with oleic acid may be produced.

The light emitting layer 150 according to the present disclosureincludes very little or none of the low molecular material included inthe hole transport layer 140. That the low molecular material does notappreciably mix with, or is not appreciably present in, the lightemitting layer may be confirmed by measuring the residual film ratio ofthe hole transport layer using the following method.

Measurement of residual film ratio.

A residual film ratio of the hole transport layer is measured by thefollowing method. The polymer coating liquid and the low molecularcoating liquid used in each device are prepared in the same ratio as thehole transport layer formed in each device, and then is applied on thequartz substrate using a spin coating method. After drying at 150° C.for 30 minutes, a film having a dry film thickness of 40 nm is formed.An absorption spectrum of the obtained film is measured with a UV-Visspectrophotometer.

A residual film ratio of the hole transport layer may be measured by thefollowing method. That is, the low molecular coating liquid used in eachdevice is coated on the quartz substrate using the spin coating method,and then dried at 150° C. for 30 minutes to form a film. The absorptionspectrum of the formed film is measured with a UV-Vis spectrophotometer(manufactured by Shimadzu Corporation, UV-1800). A peak wavelength ofthe longest wavelength of the absorption spectrum is used as thereference wavelength. Next, the polymer coating liquid and the lowmolecular coating liquid used in each device are prepared in the sameratio as the hole transport layer formed in each device, and then isapplied on the quartz substrate using a spin coating method. Afterdrying at 150° C. for 30 minutes, a film having a dry film thickness of40 nm is formed. An absorption spectrum after drying is measured with aUV-Vis spectrophotometer in the same manner as above.

Then, on the same film, a solvent of the light emitting layer is appliedby a spin coater (rotation number: 2000 rpm), and dried at 150° C. for30 minutes. An absorption spectrum after drying is measured with aUV-Vis spectrophotometer in the same manner as above. For thisabsorption spectrum, a strength ratio at the reference wavelength of theabsorption spectra before and after solvent application of the lightemitting layer is the residual film ratio of the hole transport layer.When the residual film ratio is greater than or equal to about 95%, itis determined that the hole transport layer and the light emitting layermay be stacked without film mixing, even if the light emitting layer isformed on the hole transport layer.

In addition, even though 5% of dissolved components are all lowmolecular materials, the components are diffused in a solution of thelight emitting layer, a content of the low molecular materials in thelight emitting layer is less than or equal to 0.1 weight percent, andthereby, the low molecular materials in the light emitting layer may notefficiently work. Accordingly, when the residual film ratio is greaterthan or equal to 95%, the low molecular materials may be judged to benot mingled in the light emitting layer.

The residual film ratio of the hole transport layer is greater than orequal to 95% and desirably, greater than or equal to 98%. When theresidual film ratio is less than 95%, a quantum dot EL device may not beconstructed to have a designed film thickness. In addition, there is areduction in surface smoothness of the hole transport layer,non-uniformity of a light emitting surface is caused, and a leak currentis easily generated. Accordingly, luminous efficiency and a lightemitting life-span of a device decrease.

On the light emitting layer 150, an electron transport layer 160 isformed. The electron transport layer 160 performs a function oftransporting electrons and is formed in a vacuum deposition method, aspin-coating method, an Inkjet printing method, and the like. Theelectron transport layer 160 may be, for example, formed to have athickness of greater than or equal to 15 nm and less than or equal to 70nm.

The electron transport layer 160 may be formed by using a publicly knownelectron transporting material. The publicly known electron transportingmaterial may be, for example, tris(8-quinolinolato)aluminum (Alq₃),8-hydroxyquinolinato)lithium (Liq), ZnMgO, a compound having anitrogen-containing aromatic ring, and the like. Nonlimiting examples ofthe compound having a nitrogen-containing aromatic ring may be, forexample, a compound including a pyridine ring such as1,3,5-tri[(3-pyridyl)-phen-3-yl]benzene, a compound including a triazinering such as (2,4,6-tris(3′-(pyridin-3-yl)biphenyl-3-yl)-1,3,5-triazine,a compound such as an imidazole ring such as2-(4-(N-phenylbenzoimidazolyl-1-yl-phenyl)-9,10-dinaphthylanthracene,KLET-01, KLET-02, KLET-03, KLET-10, and KLET-M1 (manufactured byChemipro Kasei Kaisha, Ltd.), and the like.

On the electron transport layer 160, an electron injection layer 170 isformed. The electron injection layer 170 performs a function offacilitating electron injection from a second electrode 180 and isformed by using a vacuum deposition method and the like. The electroninjection layer 170 may be, for example, formed to have a thickness ofgreater than or equal to 0.3 nm and less than or equal to 9 nm. Theelectron injection layer 170 may be formed of any material which ispublicly known to form the electron injection layer 170. For example,the electron injection layer 170 may be formed of a lithium compoundsuch as (8-hydroxyquinolinolato)lithium (Liq), lithium fluoride (LiF),and the like, sodium chloride (NaCl), cesium fluoride (CsF), lithiumoxide (Li₂O), barium oxide (BaO), or the like.

On the electron injection layer 170, the second electrode 180 is formed.The second electrode 180 is formed by using a vacuum deposition methodand the like. The second electrode 180 is, specifically, a cathode andformed of one having a low work function among a metal, an alloy, aconductive compound, or the like. For example, the second electrode 180may be formed as a reflective electrode by using a metal such as silver,lithium (Li), magnesium (Mg), aluminum (Al), calcium (Ca), and the like,an alloy such as aluminum-lithium (Al—Li), magnesium-indium (Mg—In),magnesium-silver (Mg—Ag), or the like. The second electrode 180 may havea thickness of greater than or equal to about 10 nm and less than orequal to about 200 nm and specifically, greater than or equal to 50 nmand less than or equal to 150 nm. Otherwise, the second electrode 180may be formed as a transmissive electrode by using a thin film formed ofthe metal material and having a thickness of less than or equal to 20 nmand a transparent conductive layer formed of indium tin oxide(In₂O₃—SnO₂), indium zinc oxide (In₂O₃—ZnO), and the like.

A stack structure of the quantum dot EL device 100 according to thepresent embodiment is not limited thereto. The quantum dot EL device 100according to the embodiment may have other publicly known stackstructures. For example, the quantum dot EL device 100 may be formed byomitting at least one among the hole injection layer 130, the holetransport layer 140, the electron transport layer 160, and the electroninjection layer 170 and in addition, additionally including a differentlayer therefrom. In addition, each layer of the quantum dot EL device100 may be respectively formed as a single layer or more than one layer.

For example, the quantum dot EL device 100 may further include a holeblocking layer between the hole transport layer 140 and the lightemitting layer 150 to prevent diffusion of excitons or holes into theelectron transport layer 160. The hole blocking layer may be, forexample, formed of an oxadiazole derivative, a triazole derivative, aphenanthroline derivative, or the like.

EXAMPLES

Although the present disclosure is described in more detail using thefollowing Examples and Comparative Examples, the technical range of thepresent disclosure is not limited to the following Examples. In thefollowing Examples, unless specifically described, each operation wasperformed at room temperature (25° C.).

Synthesis Example 1: Synthesis of Polymer Compound P-1

A polymer compound P-1 having the following structural unit according tothe following composition is synthesized based on a manufacturing methoddescribed in U.S. Patent Laid-Open Publication No. 2018/0182967. Anumber average molecular weight (Mn), a weight average molecular weight(Mw), and polydispersity (Mw/Mn) of the polymer compound P-1 aremeasured by using SEC. As a result, Mn=44,000, Mw=80,000, andMw/Mn=1.83.

Synthesis Example 2: Synthesis of Polymer Compound P-2

A polymer compound P-2 having a structure and a composition expressed byChemical Formula is synthesized based on a manufacturing methoddescribed in Japanese Patent Laid-Open Publication No. 2017-048290. Anumber average molecular weight (Mn), a weight average molecular weight(Mw), and a polydispersity (Mw/Mn) of the polymer compound P-2 aremeasured by using SEC. As a result, Mn=53,000, Mw=124,000, andMw/Mn=2.3.

Synthesis Example 3: Synthesis of Polymer Compound P-3

A polymer compound P-3 having a structural unit expressed by ChemicalFormula is synthesized in a manufacturing method described inInternational Laid-Open No. 2011/159872. A number average molecularweight (Mn), a weight average molecular weight (Mw), and apolydispersity (Mw/Mn) of the polymer compound P-3 are measured by usingSEC. As a result, Mn=141,000, Mw=434,000, and Mw/Mn=3.

Polymer Compound (TFB)

TFB (poly(9,9-dioctylfluorene-co-N-(4-butylphenyl)-diphenylamine) havinga structural unit represented by Chemical Formula 6-1 is prepared. And,TFB is manufactured by Lumitech. A number average molecular weight (Mn),a weight average molecular weight (Mw), and polydispersity (Mw/Mn) ofTFB are measured by using SEC. As a result, Mn=104,000, Mw=359,000, andMw/Mn=3.4.

Low Molecular Compound

Low molecular compounds A-1 to A-4 expressed by Chemical Formulae areprepared.

Residual film ratio Evaluation of Hole Transport Layer

Reference Example 1)

Residual film ratios of the hole transport layers are measured by thefollowing method. In other words, the polymer compound P-1 is dissolvedin xylene at a concentration of 1 weight percent to prepare a polymercoating liquid (P-1). In addition, the low molecular compound A-1 isdissolved in xylene at a concentration of 1 weight percent to prepare alow molecular coating liquid (A-1). The polymer coating liquid (P-1) andthe low molecular coating liquid (A-1) are mixed in a weight ratio of80:20 to prepare a coating liquid for a hole transport layer PA-1. Thelow molecular coating liquid (A-1) is spin-coated on a quartz substrateand dried at 150° C. for 30 minutes to form a film. Herein, anabsorption spectrum of the film is measured by using a UV-Visspectrophotometer (UV-1800, Shimadzu Corp.). A peak wavelength at thelongest wavelength of the absorption spectrum is measured and used as areference wavelength. Subsequently, the coating liquid for a holetransport layer PA-1 is spin-coated on the quartz substrate. Then, thecoated coating liquid is dried at 150° C. for 30 minutes to form a 40nm-thick film, and an absorption spectrum thereof after the drying ismeasured by equally using the UV-Vis spectrophotometer.

Subsequently, n-octane (a solvent of a light emitting layer) is coatedwith a spin coater (at 2000 rpm) on the same film and dried at 150° C.for 30 minutes. After the drying, an absorption spectrum thereof ismeasured by using the UV-Vis spectrophotometer. A strength ratio at thereference wavelength of the absorption spectrum before and after coatingthe n-octane is calculated by using this absorption spectrum to obtain aresidual film ratio of the hole transport layer. When the residual filmratio is greater than or equal to 95%, even though the light emittinglayer is formed on the hole transport layer, the hole transport layerand the light emitting layer are not mingled but stacked.

In addition, when the 5% dissolved components are all low molecularmaterials, the components are diffused in a solution of the lightemitting layer, a content of the low molecular materials in the lightemitting layer is less than or equal to 0.1 weight percent, and the lowmolecular materials may not work efficiently in the light emittinglayer. Accordingly, when the residual film ratio is greater than orequal to 95%, the low molecular materials may be judged to be notmingled into the light emitting layer.

Reference Example 2

A residual film ratio is evaluated according to the same method asReference Example 1 except that the mixing ratio of the polymer coatingliquid (P-1) and the low molecular coating liquid (A-1) is changed into70:30 (a weight ratio).

Comparative Reference Example 1

A residual film ratio is evaluated according to the same method asReference Example 1 except that the mixing ratio of the polymer coatingliquid (P-1) and the low molecular coating liquid (A-1) is changed into60:40 (a weight ratio).

Comparative Reference Example 2

A residual film ratio is evaluated according to the same method asReference Example 1 except that the mixing ratio of the polymer coatingliquid (P-1) and the low molecular coating liquid (A-1) is changed into50:50 (a weight ratio).

Comparative Reference Example 3

A residual film ratio is evaluated according to the same method asReference Example 1 except that the polymer coating liquid (P-1) is notused.

The residual film ratio evaluation results are shown in Table 1.

TABLE 1 Polymer Low molecular Polymer:low compound compound molecularResidual HOMO HOMO compound film ratio name (eV) name (eV) (weightratio) (%) Reference Example 1 P-1 5.60 A-1 5.57 80:20 99 ReferenceExample 2 P-1 5.60 A-1 5.57 70:30 98 Comparative P-1 5.60 A-1 5.57 60:4085 Reference Example 1 Comparative P-1 5.60 A-1 5.57 50:50 57 ReferenceExample 2 Comparative — — A-1 5.57  0:100 0 Reference Example 3

As shown in Table 1, when the ratio of the polymer compound exceeds 60%by weight, it is suggested that lamination may be ensured and a stabledevice may be produced.

Manufacture of Quantum Dot Electroluminescence Device

Example 1

A first electrode (a positive electrode) is prepared by coating a glasssubstrate with a stripe-shaped indium tin oxide (ITO) to form a 150nm-thick film thereon. On the glass substrate, PEDOT-PSS (Sigma-AldrichCo., Ltd.) is spin-coated to have a dry film thickness of 30 nm andthen, dried to form a 30 nm-thick hole injection layer.

Subsequently, the synthesized polymer compound P-1 is dissolved inxylene at a concentration of 1 weight percent to prepare a polymercoating liquid (P-1). In addition, the low molecular compound A-1 isdissolved in xylene as a solvent at a concentration of 1 weight percentto prepare a low molecular coating liquid (A-1). The polymer coatingliquid (P-1) and the low molecular coating liquid (A-1) are mixed in amass ratio of 80:20 to prepare a coating liquid for a hole transportlayer PA-1. On the hole injection layer, the coating liquid for a holetransport layer PA-1 is spin-coated to have a dry film thickness of 30nm and then, heated and dried at 150° C. for 30 minutes. Thereby, a 30nm-thick hole transport layer is formed.

CdSe/ZnS quantum dots (a core: CdSe, a shell: ZnS) are dispersed to be 1weight percent in n-octane to prepare quantum dot dispersion. The holetransport layer is not dissolved in n-octane. This quantum dotdispersion is spin-coated and dried to have a dry film thickness of 25nm on the hole transport layer. As a result, a 25 nm-thick quantum dotlight emitting layer is formed on the hole transport layer.

In ethanol, ZnMgO is dispersed to be 1.5 weight percent to preparedispersion for an electron transport layer. This dispersion isspin-coated to have a dry film thickness of 60 nm on the quantum dotlight emitting layer and then, dried. As a result, a 60 nm-thickelectron transport layer is formed on the quantum dot light emittinglayer.

On the electron transport layer, aluminum (Al) is vacuum-deposited toform a second electrode (a cathode) having a thickness of 100 nm. Inthis way, a quantum dot EL device (Device-1) is manufactured.

Example 2

A quantum dot EL device (Device-2) is manufactured according to the samemethod as Example 1 except that the low molecular compound A-2 is usedinstead of the low molecular compound A-1.

Example 3

A quantum dot EL device (Device-3) is manufactured according to the samemethod as Example 1 except that the low molecular compound A-3 is usedinstead of the low molecular compound A-1.

Comparative Example 1

A quantum dot EL device (Device-4) is manufactured according to the samemethod as Example 1 except that the low molecular compound A-1 is notused.

Evaluation of Quantum Dot EL Device

The quantum dot EL devices (Devices-1 to 4) according to Examples 1 to 3and Comparative Example 1 are evaluated with respect to a light emittinglife-span.

When a voltage is applied to each quantum dot EL device by using a DCconstant voltage power source (a source meter, Keyence Corp.), a currentstarts to flow at a constant voltage, and the quantum dot EL devicesemit light. The current is slowly increased, while luminance of eachdevice is measured by using a luminance-measuring device (SR-3, Topcom),until the luminance becomes 100 nits (candela per square meter (cd/m²))and then the current is kept constant at this state. The luminancemeasured by the luminance-measuring device is then slowly decreases, andtime when the luminance becomes 50% of the initial luminance is regardedas “LT50 life-span (hours)”. And, the luminance life-span of Table 1 isobtained as a relative value based on 1.00 of a measurement value ofComparative Example 1.

HOMO energy levels of the polymer material and the low molecularmaterial included in each device are obtained as ionization potentialsmeasured by using a photoelectron spectrometer AC-3 (HitachiTechnologies Co., Ltd.) in the air.

A residual film ratio of the hole transport layer is measured in thefollowing method. In other words, the low molecular coating liquid usedin each device is spin-coated on the quartz substrate and then, dried at150° C. for 30 minutes to form a film. Herein, an absorption spectrum ofthe film is measured by using a UV-Vis spectrophotometer (UV-1800,Shimadzu Corp.). A peak wavelength at the longest wavelength of theabsorption spectrum is measured and regarded as a reference wavelength.Next, the polymer coating liquid and the low molecular coating liquidused in each device are prepared in the same ratio as the hole transportlayer formed in each device and then is applied on the quartz substratein a spin coating method. Subsequently, the coated liquid is dried at150° C. for 30 minutes to form a 40 nm-thick film. After the drying, anabsorption spectrum thereof is measured by using the UV-Visspectrophotometer.

Then, n-octane (a solvent of a light emitting layer) is spin-coated (at2000 rpm) on the same film and dried at 150° C. for 30 minutes. Afterthe drying, an absorption spectrum thereof is measured by using theUV-Vis spectrophotometer. With respect to this absorption spectrum, astrength ratio at the reference wavelength of the absorption spectrumbefore and after coating the n-octane is regarded as a residual filmratio of the hole transport layer. When the residual film ratio isgreater than or equal to 95%, even though the light emitting layer isformed on the hole transport layer, the hole transport layer is notmingled but stacked with the light emitting layer.

In addition, when the 5% dissolved components are all low molecularmaterials, the low molecular materials are diffused in a solution of thelight emitting layer, and accordingly, a content of the low molecularmaterials in the light emitting layer becomes less than or equal to 0.1weight percent, and the low molecular materials may not work efficientlyin the light emitting layer. Accordingly, when the residual film ratiois greater than or equal to 95%, the low molecular materials may bejudged to be not mingled in the light emitting layer.

The results are shown in Table 2.

TABLE 2 Polymer Low molecular Polymer:low compound compound molecularResidual LT50 HOMO HOMO compound Quantum film ratio life- name (eV) name(eV) (weight ratio) dot (%) span Example 1 P-1 5.60 A-1 5.57 80:20 CdSe/99 2.74 ZnS Example 2 P-1 5.60 A-2 6.22 80:20 CdSe/ 100 1.63 ZnS Example3 P-1 5.60 A-3 6.54 80:20 CdSe/ 99 2.02 ZnS Comparative P-1 5.60 — —100:0  CdSe/ 100 1.00 Example 1 ZnS

As shown in Table 2, the quantum dot EL device of Example 1-3 exhibitsan improved LT50 life-span compared with that of Comparative Example 1.Referring to this result, the quantum dot EL device of Example 1-3exhibits satisfactory luminous efficiency and light emitting life-span.

Example 4

A quantum dot EL device (Device-5) is manufactured according to themethod as Example 1 except that InP/ZnSe/ZnS quantum dots (a core: InP,a shell: ZnSe/ZnS) are used instead of the CdSe/ZnS quantum dots.

Example 5

A quantum dot EL device (Device-6) is manufactured according to themethod as Example 1 except that the low molecular compound A-4 is usedinstead of the low molecular compound A-1.

Example 6

A quantum dot EL device (Device-7) is manufactured according to themethod as Example 4 except that the low molecular compound A-2 is usedinstead of the low molecular compound A-1.

Example 7

A quantum dot EL device (Device-8) is manufactured according to the samemethod as Example 4 except that the polymer coating liquid (P-1) and thelow molecular coating liquid (A-1) are mixed in a mass ratio of 70:30.

Comparative Example 2

A quantum dot EL device (Device-9) is manufactured according to the samemethod as Example 4 except that the low molecular coating liquid (A-1)is not used.

The quantum dot EL devices (Devices-5 to 9) are evaluated in the samemethod as above. The results are shown in Table 3. And, luminancelife-spans of Table 3 are obtained as a relative value based on 1.00 ofa measurement value of Comparative Example 2.

TABLE 3 Polymer:low Polymer Low molecular molecular compound compoundcompound Residual LT50 HOMO HOMO (weight Quantum film ratio life- name(eV) name (eV) ratio) dot (%) span Example 4 P-1 5.60 A-1 5.57 80:20InP/ 99 2.15 ZnSe/ ZnS Example 5 P-1 5.60 A-4 5.70 80:20 InP/ 98 2.00ZnSe/ ZnS Example 6 P-1 5.60 A-2 6.22 80:20 InP/ 100 239 ZnSe/ ZnSExample 7 P-1 5.60 A-1 5.57 70:30 InP/ 98 3.87 ZnSe/ ZnS Comparative P-15.60 — — 100:0  InP/ 100 1.00 Example 2 ZnSe/ ZnS

As shown in Table 3, the quantum dot EL devices according to Examples 4to 7 particularly exhibit greatly improved LT50 life-span compared withthat of Comparative Example 2. Referring to this result, the quantum dotEL devices according to Examples 4 to 7 exhibit satisfactory luminousefficiency and luminance life-span.

Example 8

A quantum dot EL device (Device-10) is manufactured according to themethod as Example 4 except that the polymer compound P-2 is used insteadof the Polymer compound P-1.

Example 9

A quantum dot EL device (Device-11) is manufactured according to themethod as Example 8 except that the low molecular compound A-2 is usedinstead of the low molecular compound A-1.

Comparative Example 3

A quantum dot EL device (Device-12) is manufactured according to themethod as Example 8 except that the low molecular compound A-1 is notused.

The quantum dot EL device (Device-10 to 12) is evaluated according tothe same method as above. The results are shown in Table 4. Luminancelife-spans of Table 4 are obtained as a relative value based on 1.00 ofa measurement value of Comparative Example 3.

TABLE 4 Polymer:low Polymer Low molecular molecular compound compoundcompound Residual LT50 HOMO HOMO (weight Quantum film ratio life- name(eV) name (eV) ratio) dot (%) span Example 8 P-2 5.40 A-1 5.57 80:20InP/ 99 2.00 ZnSe/ ZnS Example 9 P-2 5.40 A-2 6.22 80:20 InP/ 99 1.56ZnSe/ ZnS Comparative P-2 5.40 — — 100:0  InP/ 100 1.00 Example 3 ZnSe/ZnS

As shown in Table 4, the quantum dot EL devices according to Examples 8to 9 exhibit a greatly improved LT50 life-span compared with that ofComparative Example 3. Referring to this result, the quantum dot ELdevices of Examples 8 to 9 exhibit satisfactory luminous efficiency andluminance life-span.

Example 10

A quantum dot EL device (Device-13) is manufactured according to themethod as Example 4 except that the polymer compound P-3 is used insteadof the polymer compound P-1.

Example 11

A quantum dot EL device (Device-14) is manufactured according to themethod as Example 10 except that the low molecular compound A-2 is usedinstead of the low molecular compound A-1.

Comparative Example 4

A quantum dot EL device (Device-15) is manufactured according to thesame method as Example 10 except that the low molecular compound A-1 isnot used.

The quantum dot EL devices (Devices-13 to 15) are evaluated according tothe same method as above. The results are shown in Table 5. Luminancelife-spans of Table 5 are obtained as a relative value based on 1.00 ofa measurement value of Comparative Example 4.

TABLE 5 Polymer Low molecular Polymer:Low compound compound molecularResidual LT50 HOMO HOMO (mass Quantum film ratio life- name (eV) name(eV) ratio) dot (%) span Example 10 P-3 5.70 A-1 5.57 80:20 InP/ 1001.33 ZnSe/ ZnS Example 11 P-3 5.70 A-2 6.22 80:20 InP/ 100 1.17 ZnSe/ZnS Comparative P-3 5.70 — — 100:0  InP/ 100 1.00 Example 4 ZnSe/ ZnS

As shown in Table 5, the quantum dot EL devices according to Examples 10to 11 exhibit a greatly improved LT50 life-span compared with that ofComparative Example 4.

Referring to this result, the quantum dot EL devices of Examples 10 to11 exhibit satisfactory luminous efficiency and luminance life-span.

Example 12

A quantum dot EL device (Device-16) is manufactured according to themethod as Example 4 except that the TFB is used instead of the polymercompound P-1.

Comparative Example 5

A quantum dot EL device (Device-17) is manufactured according to themethod as Example 12 except that a coating solution including TFB is notused.

The quantum dot EL devices (Devices-16 to 17) are evaluated according tothe same method as above. The results are shown in Table 6. Luminancelife-spans of Table 5 are obtained as a relative value based on 1.00 ofa measurement value of Comparative Example 5.

TABLE 6 Polymer Low molecular Polymer:Low compound compound molecularResidual LT50 HOMO HOMO (weight Quantum film ratio life- name (eV) name(eV) ratio) dot (%) span Example 12 TFB 5.54 A-1 5.57 80:20 InP/ 98 1.21ZnSe/ ZnS Comparative TFB 5.54 — — 100:0  InP/ 100 1.00 Example 5 ZnSe/ZnS

As shown in Table 6, the quantum dot EL device according to Example 12exhibits a greatly improved LT50 life-span compared with that ofComparative Example 5. Referring to this result, the quantum dot ELdevice of Example 12 exhibits satisfactory luminous efficiency andluminance life-span.

Hereinafter, a model device is manufactured, and an experiment isperformed to examine a reason of improving characteristics thereof.

Reference Experiment: Characteristic Evaluation of Model Device

Reference Example 3

An electron blocking layer is formed by sequentially vacuum-depositingα-NPD (N,N′-di-1-naphthyl-N,N′-diphenylbenzidine) and HAT-CN(dipyrazino[2,3-f:2′,3′-h]quinoxaline-2,3,6,7,10,11-hexacarbonitrile) tohave each thickness of 36 nm and 10 nm instead of the electron transportlayer. A hole only device (H-Device-1) is manufactured according to themethod as Example 4 except for this.

Reference Example 4

The electron blocking layer is formed by sequentially vacuum depositingα-NPD and HAT-CN to have each thickness of 36 nm and 10 nm instead ofthe electron transport layer. A hole only device (H-Device-2) ismanufactured according to the method as Example 6 except for this.

Comparative Reference Example 4

A hole only device (H-Device-3) is manufactured according to the methodas Example 2 except that the electron blocking layer is formed bysequentially vacuum-depositing α-NPD and HAT-ON to have each thicknessof 36 nm and 10 nm instead of the electron transport layer.

The quantum dot EL devices (Devices-3 to 5) are evaluated with respectto a residual film ratio according to the same method as above. Inaddition, a voltage is applied to each H-device by using the same DCconstant voltage power source as used above in the evaluation of thequantum dot EL devices, and then, voltage-current characteristicsthereof are measured by slowly increasing a current, and a drivingvoltage at 2 mA/cm² is calculated.

The results are shown in Table 7. And, driving voltages of Table 7 areobtained as a relative value based on 1.00 of a measurement value ofComparative Example 4.

TABLE 7 Polymer Low molecular compound compound Polymer Residual LT50HOMO HOMO (weight Quantum film ratio life- name (eV) name (eV) ratio)dot (%) span Reference P-1 5.60 A-1 5.57 80:20 InP/ 99 0.79 Example 3ZnSe/ ZnS Reference P-1 5.60 A-2 6.22 80:20 InP/ 99 0.93 Example 4 ZnSe/ZnS Comparative P-1 5.60 — — 100:0 InP/ 100 1.00 Reference ZnSe/ Example4 ZnS

As shown in Table 7, the quantum dot EL devices according to ReferenceExamples 3 to 4 use a low driving voltage compared with that ofComparative Reference Example 4. Referring to this result, the quantumdot EL devices of Examples 4 and 6 exhibit improved hole injectabilityand transportation properties and thus a long life-span effect.

Reference Example 5

An electron blocking layer is formed by sequentially vacuum-depositingα-NPD and HAT-CN with a thickness of 36 nm and 10 nm, respectively,instead of the electron transport layer. A hole only device (H-Device-4)is manufactured according to the method as Example 10 except for this.

Reference Example 6

An electron blocking layer is formed by sequentially vacuum-depositingα-NPD and HAT-CN with a thickness of 36 nm and 10 nm, respectively,instead of the electron transport layer. A hole only device (H-Device-5)is manufactured according to the method as Example 11 except for this.

Comparative Reference Example 5

A hole only device (H-Device-6) is manufactured according to the methodas Comparative Example 6 except that the electron blocking layer isformed by sequentially vacuum-depositing α-NPD and HAT-CN with athickness of 36 nm and 10 nm, respectively, instead of the electrontransport layer.

The hole only devices (H-Devices-4 to 6) are evaluated with respect to aresidual film ratio and a driving voltage according to the same methodas above.

The results are shown in Table 8. And, driving voltages of Table 7 areobtained as a relative value based on 1.00 of a measurement value ofComparative Example 5.

TABLE 8 Polymer Low molecular Polymer:Low Driving compound compoundmolecular Residual voltage HOMO HOMO (weight Quantum film ratio @ 2 name(eV) name (eV) ratio) dot (%) mA/cm² Reference P-3 5.70 A-1 5.57 80:20InP/ 99 0.76 Example 5 ZnSe/ ZnS Reference P-3 5.70 A-2 6.22 80:20 InP/99 0.85 Example 6 ZnSe/ ZnS Comparative P-3 5.70 — — 100:0  InP/ 1001.00 Reference ZnSe/ Example 5 ZnS

As shown in Table 8, the quantum dot EL devices according to ReferenceExamples 5 to 6 use a low driving voltage compared with that ofComparative Reference Example 5. Referring to this result, the quantumdot EL devices of Examples 10 to 11 exhibit improved hole injectabilityand transportation properties and thus a long life-span effect.

While this disclosure has been described in connection with what ispresently considered to be practical example embodiments, it is to beunderstood that the invention is not limited to the disclosedembodiments. On the contrary, it is intended to cover variousmodifications and equivalent arrangements included within the spirit andscope of the appended claims.

Description of Symbols 100: quantum dot electroluminescence device(quantum dot EL device) 110: substrate 120: first electrode 130: holeinjection layer 140: hole transport layer 150: light emitting layer 160:electron transport layer 170: electron injection layer 180: secondelectrode

What is claimed is:
 1. A quantum dot electroluminescence device,comprising a hole transport layer, an electron transport layer, and alight emitting layer disposed between the hole transport layer and theelectron transport layer, wherein the hole transport layer comprises apolymer material and a low molecular material, the light emitting layercomprises a quantum dot having a core-shell structure, and a residualfilm ratio of the hole transport layer is greater than or equal to about95%.
 2. The quantum dot electroluminescence device of claim 1, whereinthe polymer material has an amine structure.
 3. The quantum dotelectroluminescence device of claim 1, wherein a content ratio of thepolymer material in the hole transport layer is greater than about 60weight percent and less than about 100 weight percent, based on 100weight percent of the polymer material and the low molecular material.4. The quantum dot electroluminescence device of claim 1, wherein thepolymer compound 1 comprises a segment of an alternate copolymer of astructural unit represented by Chemical Formula 1

wherein, in Chemical Formula 1, X is a group represented by ChemicalFormula 2, Y is a substituted or unsubstituted C6 to 60 divalentaromatic hydrocarbon group, or a substituted or unsubstituted divalentaromatic heterocyclic group having 3 to 60 ring-forming atoms;

wherein in Chemical Formula 2, Ar₁ is a substituted or unsubstituted C6to C60 trivalent aromatic hydrocarbon group, or a substituted orunsubstituted trivalent aromatic heterocyclic group having 3 to 60ring-forming atoms, Ar₂ and Ar₃ are independently a substituted orunsubstituted C6 to C60 monovalent aromatic hydrocarbon group, or asubstituted or unsubstituted monovalent aromatic heterocyclic grouphaving 3 to 60 ring-forming atoms, L₁ and L₂ are independently a singlebond, a substituted or unsubstituted C6 to C60 divalent aromatichydrocarbon group, or a substituted or unsubstituted divalent aromaticheterocyclic group having 3 to 60 ring-forming atoms, R₁ and R₂ areindependently, a substituted or unsubstituted C1 to C20 alkyl group, asubstituted or unsubstituted C1 to C20 alkoxy group, a substituted orunsubstituted C6 to C60 monovalent aromatic hydrocarbon group, or asubstituted or unsubstituted monovalent aromatic heterocyclic grouphaving 3 to 60 ring-forming atoms, or R₁ and R₂ are optionally linked toeach other to form a ring, a is an integer of 0 to 4, b is an integer of0 to 3, Z₁ to Z₄ are independently a nitrogen atom, CH or CR₁; and Z₅ toZ₈ are independently a nitrogen atom, CH, or CR₂, and where one of Z₅ toZ₈ is connected to L₂.
 5. The quantum dot electroluminescence device ofclaim 1, wherein the polymer material comprises a repeating unitrepresented by Chemical Formula P-2:

wherein, in Chemical Formula P-2, R₁, R₂, and R₃ are independently ahydrogen atom, a substituted or unsubstituted C1 to C10 alkyl group, ora substituted or unsubstituted ring-forming C6 to C30 aryl group, m isan integer of 1 to 20, F and F′ are independently a divalent grouphaving a fluorene structure including azafluorene, and A is a divalentgroup represented by Chemical Formula (P-21),

wherein, in Chemical Formula (P-21), L₁ and L₂ are independently asingle bond, a substituted or unsubstituted C1 to C20 alkylene group, asubstituted or unsubstituted ring-forming C3 to C16 cycloalkylene group,a substituted or unsubstituted ring-forming C6 to C30 arylene group, asubstituted or unsubstituted C1 to C20 oxyalkylene group, a substitutedor unsubstituted ring-forming C3 to C16 oxycycloalkylene group, asubstituted or unsubstituted ring-forming C6 to C30 oxy arylene group, asubstituted or unsubstituted C7 to C40 aralkylene group, a substitutedor unsubstituted ring-forming C5 to C30 heteroarylene group, asubstituted or unsubstituted C1 to C20 aminoalkylene group, asubstituted or unsubstituted ring-forming C6 to C30 aminoarylene group,or a silylene group substituted with an alkyl group or an aryl group,Ar₁ is hydrogen, a substituted or unsubstituted C1 to C20 alkyl group, asubstituted or unsubstituted ring-forming C3 to C16 cycloalkyl group, asubstituted or unsubstituted ring-forming C6 to C30 aryl group, asubstituted or unsubstituted C1 to C20 alkoxy group, a substituted orunsubstituted ring-forming C3 to C16 cycloalkoxy group, a substituted orunsubstituted ring-forming C6 to C30 aryloxy group, a substituted orunsubstituted C7 to C40 aralkyl group, a substituted or unsubstitutedring-forming C5 to C30 heteroaryl group, an alkylamino group including asubstituted or unsubstituted C1 to C20 alkyl group, a substituted orunsubstituted ring-forming C6 to C30 arylamino group, or a cyclicsubstituent formed by combining these substituents and L₁ or L₂, * is alinking portion with another substituent, and R₄ is hydrogen, a halogenatom, a hydroxy group, an amino group, a nitro group, a cyano group, asubstituted or unsubstituted silyl group, a substituted or unsubstitutedC1 to C20 alkyl group, a substituted or unsubstituted ring-forming C3 toC16 cycloalkyl group, a substituted or unsubstituted ring-forming C6 toC30 aryl group, a substituted or unsubstituted C1 to C20 alkoxy group, asubstituted or unsubstituted ring-forming C3 to C16 cycloalkoxy group, asubstituted or unsubstituted ring-forming C6 to C30 aryloxy group, asubstituted or unsubstituted C7 to C40 aralkyl group, a substituted orunsubstituted ring-forming C5 to C30 heteroaryl group, an alkylaminogroup including a substituted or unsubstituted C1 to C20 alkyl group, ora substituted or unsubstituted ring-forming C6 to C30 arylamino group.6. The quantum dot electroluminescence device of claim 1, wherein thepolymer material comprises a polymer compound represented by ChemicalFormula (I) or Chemical Formula (I′):

wherein, in Chemical Formulae (I) and (I′): Ar¹ and Ar² are the same ordifferent and an aryl group; R¹ to R⁵ are independently the same ordifferent and are D, F, alkyl, aryl, alkoxy, silyl, or a cross-linkinggroup; R⁶ is the same or different and is H, D, or a halogen; a to e areindependently an integer of 0 to 4; f is 1 or 2; g is 0, 1, or 2; h is 1or 2; and n is an integer of greater than
 0. 7. The quantum dotelectroluminescence device of claim 1, wherein the polymer materialcomprises a copolymer represented by Chemical Formula (I-2):

wherein, in Chemical Formula (I-2), A is a monomer unit comprising atleast one triarylamine group, B′ is a monomer unit having at least threelinking points in the copolymer, C′ is an aromatic monomer unit or adeuterated analog thereof, E is the same or different and isindependently H, D, a halide, an alkyl group, a silyl group, a germanylgroup, an aryl group, an arylamino group, a siloxane group, across-linking group, a deuterated alkyl group, a deuterated silyl group,a deuterated germanyl group, a deuterated aryl group, a deuteratedarylamino group, a deuterated siloxane group, or a deuteratedcross-linking group, and a, b, and c are mole fractions, the same ordifferent, a+b+c=1, and a and b are not zero.
 8. The quantum dotelectroluminescence device of claim 1, wherein the polymer materialcomprises a polymer compound having a structural unit (A) represented byChemical Formula (5-1):

wherein, in Chemical Formula (5-1), Ar₁ is independently a C6 to C25aromatic hydrocarbon group which may be optionally substituted, or a C12to C25 heterocyclic aromatic group which may be optionally substituted;Ar₂ is independently a C6 to C25 aromatic hydrocarbon group which may beoptionally substituted, or a C12 to C25 divalent heterocyclic aromaticgroup which may be optionally substituted; and R₁ is independently ahydrogen atom, a C1 to C12 linear, branched, or cyclic hydrocarbongroup, or a C6 to C25 divalent aromatic hydrocarbon group, each of whichis optionally substituted.
 9. The quantum dot electroluminescence deviceof claim 1, wherein the polymer material comprises a polymer compoundhaving at least one of a structural unit represented by Chemical Formula(6-1) or a structural unit represented by Chemical Formula (6-2):


10. The quantum dot electroluminescence device of claim 1, wherein thelow molecular material is a hole transporting material or a wide gapmaterial, and the low molecular material is included among one or morepolymer materials.
 11. The quantum dot electroluminescence device ofclaim 10, wherein the hole transporting material is at least one of thelow molecular compounds represented by Chemical Formula (L1) to ChemicalFormula (L4):

wherein, in Chemical Formula (L1), R is independently a hydrogen atom, adeuterium atom, or a monovalent organic group, or a plurality of R's arelinked to each other to form a ring, Ar_(a) is a group represented byChemical Formula (L1-a), a plurality of Ar_(a)'s are the same ordifferent, and optionally a plurality of Ar_(a)'s are linked to eachother to form a ring, and Ar_(b) is a group represented by ChemicalFormula (L1-b);

wherein, in Chemical Formula (L1-a), R is independently a hydrogen atom,a deuterium atom, or a monovalent organic group, and optionally aplurality of R's are linked to each other to form a ring. n is aninteger of 0 to 3, and * represents a linking portion with an adjacentatom;

wherein, in Chemical Formula (L1-b), R is independently a hydrogen atom,a deuterium atom, or a monovalent organic group, or a plurality of R'sare linked to each other to form a ring, m is an integer of 0 to 2,and * represents a linking portion with an adjacent atom;

wherein, in Chemical Formula (L2), Ar_(a) is a group represented byChemical Formula (L2-a), X is a group represented by Chemical Formula(L2-b), a plurality of X's are the same or different, and optionally, aplurality of X's are linked to each other to form a ring;

wherein, in Chemical Formula (L2-a), R is independently a hydrogen atom,a deuterium atom, or a monovalent organic group, or optionally aplurality of R's are linked to each other to form a ring, Z is a C1 toC12 linear or branched alkyl group, and * represents a linking portionwith an adjacent atom;

wherein, in Chemical Formula (L2-b), R is independently a hydrogen atom,a deuterium atom, or a monovalent organic group, or optionally aplurality of R's are linked to each other to form a ring, n is aninteger of 0 to 3, and * represents a linking portion with an adjacentatom;

wherein, in Chemical Formula (L3), R₁, R₂, and R₃ are independently ahydrogen atom, a monovalent hydrocarbon group, or a monovalent aromatichydrocarbon group, or optionally the two R₁'s are linked to each otherto form a ring, X₁ is a hydrogen atom or a group represented by ChemicalFormula (L3-a), and X₂ is a group represented by Chemical Formula(L3-a);

wherein, in Chemical Formula (L3-a), R₄ and R₅ are independently ahydrogen atom or a monovalent hydrocarbon group, and l, m, and n areindependently an integer of 0 to 3;

wherein, in Chemical Formula (L4), Y is a carbon atom or a silicon atom,R₁ to R₃ are independently a hydrogen atom, a monovalent hydrocarbongroup, or a monovalent aromatic hydrocarbon group, or two R₁'s arelinked to each other to form a ring, X₁ is a hydrogen atom or a grouprepresented by Chemical Formula (L4-a), and X₂ is a group represented byChemical Formula (L4-a);

wherein, in Chemical Formula (L4-a), R₄ and R₅ are independently ahydrogen atom or a monovalent hydrocarbon group, and l, m, and n areindependently an integer of 0 to
 3. 12. The quantum dotelectroluminescence device of claim 10, wherein the wide gap material isa low molecular compound represented by Chemical Formula (L5) orChemical Formula (L6):

wherein, in Chemical Formula (L5), m and n are independently an integerof 0 to 3, R is independently a hydrogen atom, a monovalent organicgroup, or two or more adjacent R's are condensed or linked to each otherto form a ring, X is O, S, NR′, or C(R″)₂, and R′ and R″ areindependently a hydrogen atom or a monovalent organic group:

wherein, in Chemical Formula (L6), m and n are independently an integerof 0 to 3, and R is independently a hydrogen atom or a monovalentorganic group or two or more adjacent R's are condensed or linked toeach other to form a ring,